diff --git a/bower.json b/bower.json
index dcba48c..de24c55 100644
--- a/bower.json
+++ b/bower.json
@@ -1,6 +1,6 @@
 {
   "name": "aurelia-polyfills",
-  "version": "1.1.1",
+  "version": "1.2.0",
   "description": "The minimal set of polyfills that the Aurelia platform needs to run on ES5 browsers.",
   "keywords": [
     "aurelia",
diff --git a/dist/amd/aurelia-polyfills.js b/dist/amd/aurelia-polyfills.js
index 93abe93..5032dd1 100644
--- a/dist/amd/aurelia-polyfills.js
+++ b/dist/amd/aurelia-polyfills.js
@@ -7,266 +7,273 @@ define(['aurelia-pal'], function (_aureliaPal) {
     return obj && typeof Symbol === "function" && obj.constructor === Symbol ? "symbol" : typeof obj;
   };
 
-  (function (Object, GOPS) {
-    'use strict';
-
-    if (GOPS in Object) return;
-
-    var setDescriptor,
-        G = _aureliaPal.PLATFORM.global,
-        id = 0,
-        random = '' + Math.random(),
-        prefix = '__\x01symbol:',
-        prefixLength = prefix.length,
-        internalSymbol = '__\x01symbol@@' + random,
-        DP = 'defineProperty',
-        DPies = 'defineProperties',
-        GOPN = 'getOwnPropertyNames',
-        GOPD = 'getOwnPropertyDescriptor',
-        PIE = 'propertyIsEnumerable',
-        gOPN = Object[GOPN],
-        gOPD = Object[GOPD],
-        create = Object.create,
-        keys = Object.keys,
-        defineProperty = Object[DP],
-        $defineProperties = Object[DPies],
-        descriptor = gOPD(Object, GOPN),
-        ObjectProto = Object.prototype,
-        hOP = ObjectProto.hasOwnProperty,
-        pIE = ObjectProto[PIE],
-        toString = ObjectProto.toString,
-        indexOf = Array.prototype.indexOf || function (v) {
-      for (var i = this.length; i-- && this[i] !== v;) {}
-      return i;
-    },
-        addInternalIfNeeded = function addInternalIfNeeded(o, uid, enumerable) {
-      if (!hOP.call(o, internalSymbol)) {
-        defineProperty(o, internalSymbol, {
-          enumerable: false,
-          configurable: false,
-          writable: false,
-          value: {}
-        });
-      }
-      o[internalSymbol]['@@' + uid] = enumerable;
-    },
-        createWithSymbols = function createWithSymbols(proto, descriptors) {
-      var self = create(proto);
-      gOPN(descriptors).forEach(function (key) {
-        if (propertyIsEnumerable.call(descriptors, key)) {
-          $defineProperty(self, key, descriptors[key]);
-        }
-      });
-      return self;
-    },
-        copyAsNonEnumerable = function copyAsNonEnumerable(descriptor) {
-      var newDescriptor = create(descriptor);
-      newDescriptor.enumerable = false;
-      return newDescriptor;
-    },
-        get = function get() {},
-        onlyNonSymbols = function onlyNonSymbols(name) {
-      return name != internalSymbol && !hOP.call(source, name);
-    },
-        onlySymbols = function onlySymbols(name) {
-      return name != internalSymbol && hOP.call(source, name);
-    },
-        propertyIsEnumerable = function propertyIsEnumerable(key) {
-      var uid = '' + key;
-      return onlySymbols(uid) ? hOP.call(this, uid) && this[internalSymbol]['@@' + uid] : pIE.call(this, key);
-    },
-        setAndGetSymbol = function setAndGetSymbol(uid) {
-      var descriptor = {
-        enumerable: false,
-        configurable: true,
-        get: get,
-        set: function set(value) {
-          setDescriptor(this, uid, {
+  if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
+    (function (Object, GOPS) {
+      'use strict';
+
+      if (GOPS in Object) return;
+
+      var setDescriptor,
+          G = _aureliaPal.PLATFORM.global,
+          id = 0,
+          random = '' + Math.random(),
+          prefix = '__\x01symbol:',
+          prefixLength = prefix.length,
+          internalSymbol = '__\x01symbol@@' + random,
+          DP = 'defineProperty',
+          DPies = 'defineProperties',
+          GOPN = 'getOwnPropertyNames',
+          GOPD = 'getOwnPropertyDescriptor',
+          PIE = 'propertyIsEnumerable',
+          gOPN = Object[GOPN],
+          gOPD = Object[GOPD],
+          create = Object.create,
+          keys = Object.keys,
+          defineProperty = Object[DP],
+          $defineProperties = Object[DPies],
+          descriptor = gOPD(Object, GOPN),
+          ObjectProto = Object.prototype,
+          hOP = ObjectProto.hasOwnProperty,
+          pIE = ObjectProto[PIE],
+          toString = ObjectProto.toString,
+          indexOf = Array.prototype.indexOf || function (v) {
+        for (var i = this.length; i-- && this[i] !== v;) {}
+        return i;
+      },
+          addInternalIfNeeded = function addInternalIfNeeded(o, uid, enumerable) {
+        if (!hOP.call(o, internalSymbol)) {
+          defineProperty(o, internalSymbol, {
             enumerable: false,
-            configurable: true,
-            writable: true,
-            value: value
+            configurable: false,
+            writable: false,
+            value: {}
           });
-          addInternalIfNeeded(this, uid, true);
         }
-      };
-      defineProperty(ObjectProto, uid, descriptor);
-      return source[uid] = defineProperty(Object(uid), 'constructor', sourceConstructor);
-    },
-        _Symbol = function _Symbol2(description) {
-      if (this && this !== G) {
-        throw new TypeError('Symbol is not a constructor');
-      }
-      return setAndGetSymbol(prefix.concat(description || '', random, ++id));
-    },
-        source = create(null),
-        sourceConstructor = { value: _Symbol },
-        sourceMap = function sourceMap(uid) {
-      return source[uid];
-    },
-        $defineProperty = function defineProp(o, key, descriptor) {
-      var uid = '' + key;
-      if (onlySymbols(uid)) {
-        setDescriptor(o, uid, descriptor.enumerable ? copyAsNonEnumerable(descriptor) : descriptor);
-        addInternalIfNeeded(o, uid, !!descriptor.enumerable);
-      } else {
-        defineProperty(o, key, descriptor);
-      }
-      return o;
-    },
-        $getOwnPropertySymbols = function getOwnPropertySymbols(o) {
-      var cof = toString.call(o);
-      o = cof === '[object String]' ? o.split('') : Object(o);
-      return gOPN(o).filter(onlySymbols).map(sourceMap);
-    };
-
-    descriptor.value = $defineProperty;
-    defineProperty(Object, DP, descriptor);
-
-    descriptor.value = $getOwnPropertySymbols;
-    defineProperty(Object, GOPS, descriptor);
-
-    descriptor.value = function getOwnPropertyNames(o) {
-      return gOPN(o).filter(onlyNonSymbols);
-    };
-    defineProperty(Object, GOPN, descriptor);
-
-    descriptor.value = function defineProperties(o, descriptors) {
-      var symbols = $getOwnPropertySymbols(descriptors);
-      if (symbols.length) {
-        keys(descriptors).concat(symbols).forEach(function (uid) {
-          if (propertyIsEnumerable.call(descriptors, uid)) {
-            $defineProperty(o, uid, descriptors[uid]);
+        o[internalSymbol]['@@' + uid] = enumerable;
+      },
+          createWithSymbols = function createWithSymbols(proto, descriptors) {
+        var self = create(proto);
+        gOPN(descriptors).forEach(function (key) {
+          if (propertyIsEnumerable.call(descriptors, key)) {
+            $defineProperty(self, key, descriptors[key]);
           }
         });
-      } else {
-        $defineProperties(o, descriptors);
-      }
-      return o;
-    };
-    defineProperty(Object, DPies, descriptor);
+        return self;
+      },
+          copyAsNonEnumerable = function copyAsNonEnumerable(descriptor) {
+        var newDescriptor = create(descriptor);
+        newDescriptor.enumerable = false;
+        return newDescriptor;
+      },
+          get = function get() {},
+          onlyNonSymbols = function onlyNonSymbols(name) {
+        return name != internalSymbol && !hOP.call(source, name);
+      },
+          onlySymbols = function onlySymbols(name) {
+        return name != internalSymbol && hOP.call(source, name);
+      },
+          propertyIsEnumerable = function propertyIsEnumerable(key) {
+        var uid = '' + key;
+        return onlySymbols(uid) ? hOP.call(this, uid) && this[internalSymbol]['@@' + uid] : pIE.call(this, key);
+      },
+          setAndGetSymbol = function setAndGetSymbol(uid) {
+        var descriptor = {
+          enumerable: false,
+          configurable: true,
+          get: get,
+          set: function set(value) {
+            setDescriptor(this, uid, {
+              enumerable: false,
+              configurable: true,
+              writable: true,
+              value: value
+            });
+            addInternalIfNeeded(this, uid, true);
+          }
+        };
+        defineProperty(ObjectProto, uid, descriptor);
+        return source[uid] = defineProperty(Object(uid), 'constructor', sourceConstructor);
+      },
+          _Symbol = function _Symbol2(description) {
+        if (this && this !== G) {
+          throw new TypeError('Symbol is not a constructor');
+        }
+        return setAndGetSymbol(prefix.concat(description || '', random, ++id));
+      },
+          source = create(null),
+          sourceConstructor = { value: _Symbol },
+          sourceMap = function sourceMap(uid) {
+        return source[uid];
+      },
+          $defineProperty = function defineProp(o, key, descriptor) {
+        var uid = '' + key;
+        if (onlySymbols(uid)) {
+          setDescriptor(o, uid, descriptor.enumerable ? copyAsNonEnumerable(descriptor) : descriptor);
+          addInternalIfNeeded(o, uid, !!descriptor.enumerable);
+        } else {
+          defineProperty(o, key, descriptor);
+        }
+        return o;
+      },
+          $getOwnPropertySymbols = function getOwnPropertySymbols(o) {
+        var cof = toString.call(o);
+        o = cof === '[object String]' ? o.split('') : Object(o);
+        return gOPN(o).filter(onlySymbols).map(sourceMap);
+      };
 
-    descriptor.value = propertyIsEnumerable;
-    defineProperty(ObjectProto, PIE, descriptor);
+      descriptor.value = $defineProperty;
+      defineProperty(Object, DP, descriptor);
 
-    descriptor.value = _Symbol;
-    defineProperty(G, 'Symbol', descriptor);
+      descriptor.value = $getOwnPropertySymbols;
+      defineProperty(Object, GOPS, descriptor);
 
-    descriptor.value = function (key) {
-      var uid = prefix.concat(prefix, key, random);
-      return uid in ObjectProto ? source[uid] : setAndGetSymbol(uid);
-    };
-    defineProperty(_Symbol, 'for', descriptor);
+      descriptor.value = function getOwnPropertyNames(o) {
+        return gOPN(o).filter(onlyNonSymbols);
+      };
+      defineProperty(Object, GOPN, descriptor);
+
+      descriptor.value = function defineProperties(o, descriptors) {
+        var symbols = $getOwnPropertySymbols(descriptors);
+        if (symbols.length) {
+          keys(descriptors).concat(symbols).forEach(function (uid) {
+            if (propertyIsEnumerable.call(descriptors, uid)) {
+              $defineProperty(o, uid, descriptors[uid]);
+            }
+          });
+        } else {
+          $defineProperties(o, descriptors);
+        }
+        return o;
+      };
+      defineProperty(Object, DPies, descriptor);
 
-    descriptor.value = function (symbol) {
-      return hOP.call(source, symbol) ? symbol.slice(prefixLength * 2, -random.length) : void 0;
-    };
-    defineProperty(_Symbol, 'keyFor', descriptor);
+      descriptor.value = propertyIsEnumerable;
+      defineProperty(ObjectProto, PIE, descriptor);
 
-    descriptor.value = function getOwnPropertyDescriptor(o, key) {
-      var descriptor = gOPD(o, key);
-      if (descriptor && onlySymbols(key)) {
-        descriptor.enumerable = propertyIsEnumerable.call(o, key);
-      }
-      return descriptor;
-    };
-    defineProperty(Object, GOPD, descriptor);
+      descriptor.value = _Symbol;
+      defineProperty(G, 'Symbol', descriptor);
 
-    descriptor.value = function (proto, descriptors) {
-      return arguments.length === 1 ? create(proto) : createWithSymbols(proto, descriptors);
-    };
-    defineProperty(Object, 'create', descriptor);
+      descriptor.value = function (key) {
+        var uid = prefix.concat(prefix, key, random);
+        return uid in ObjectProto ? source[uid] : setAndGetSymbol(uid);
+      };
+      defineProperty(_Symbol, 'for', descriptor);
 
-    descriptor.value = function () {
-      var str = toString.call(this);
-      return str === '[object String]' && onlySymbols(this) ? '[object Symbol]' : str;
-    };
-    defineProperty(ObjectProto, 'toString', descriptor);
+      descriptor.value = function (symbol) {
+        return hOP.call(source, symbol) ? symbol.slice(prefixLength * 2, -random.length) : void 0;
+      };
+      defineProperty(_Symbol, 'keyFor', descriptor);
 
-    try {
-      setDescriptor = create(defineProperty({}, prefix, {
-        get: function get() {
-          return defineProperty(this, prefix, { value: false })[prefix];
+      descriptor.value = function getOwnPropertyDescriptor(o, key) {
+        var descriptor = gOPD(o, key);
+        if (descriptor && onlySymbols(key)) {
+          descriptor.enumerable = propertyIsEnumerable.call(o, key);
         }
-      }))[prefix] || defineProperty;
-    } catch (o_O) {
-      setDescriptor = function setDescriptor(o, key, descriptor) {
-        var protoDescriptor = gOPD(ObjectProto, key);
-        delete ObjectProto[key];
-        defineProperty(o, key, descriptor);
-        defineProperty(ObjectProto, key, protoDescriptor);
+        return descriptor;
       };
-    }
-  })(Object, 'getOwnPropertySymbols');
-
-  (function (O, S) {
-    var dP = O.defineProperty,
-        ObjectProto = O.prototype,
-        toString = ObjectProto.toString,
-        toStringTag = 'toStringTag',
-        descriptor;
-    ['iterator', 'match', 'replace', 'search', 'split', 'hasInstance', 'isConcatSpreadable', 'unscopables', 'species', 'toPrimitive', toStringTag].forEach(function (name) {
-      if (!(name in Symbol)) {
-        dP(Symbol, name, { value: Symbol(name) });
-        switch (name) {
-          case toStringTag:
-            descriptor = O.getOwnPropertyDescriptor(ObjectProto, 'toString');
-            descriptor.value = function () {
-              var str = toString.call(this),
-                  tst = typeof this === 'undefined' || this === null ? undefined : this[Symbol.toStringTag];
-              return typeof tst === 'undefined' ? str : '[object ' + tst + ']';
-            };
-            dP(ObjectProto, 'toString', descriptor);
-            break;
-        }
-      }
-    });
-  })(Object, Symbol);
+      defineProperty(Object, GOPD, descriptor);
 
-  (function (Si, AP, SP) {
+      descriptor.value = function (proto, descriptors) {
+        return arguments.length === 1 ? create(proto) : createWithSymbols(proto, descriptors);
+      };
+      defineProperty(Object, 'create', descriptor);
 
-    function returnThis() {
-      return this;
-    }
+      descriptor.value = function () {
+        var str = toString.call(this);
+        return str === '[object String]' && onlySymbols(this) ? '[object Symbol]' : str;
+      };
+      defineProperty(ObjectProto, 'toString', descriptor);
 
-    if (!AP[Si]) AP[Si] = function () {
-      var i = 0,
-          self = this,
-          iterator = {
-        next: function next() {
-          var done = self.length <= i;
-          return done ? { done: done } : { done: done, value: self[i++] };
+      try {
+        setDescriptor = create(defineProperty({}, prefix, {
+          get: function get() {
+            return defineProperty(this, prefix, { value: false })[prefix];
+          }
+        }))[prefix] || defineProperty;
+      } catch (o_O) {
+        setDescriptor = function setDescriptor(o, key, descriptor) {
+          var protoDescriptor = gOPD(ObjectProto, key);
+          delete ObjectProto[key];
+          defineProperty(o, key, descriptor);
+          defineProperty(ObjectProto, key, protoDescriptor);
+        };
+      }
+    })(Object, 'getOwnPropertySymbols');
+
+    (function (O, S) {
+      var dP = O.defineProperty,
+          ObjectProto = O.prototype,
+          toString = ObjectProto.toString,
+          toStringTag = 'toStringTag',
+          descriptor;
+      ['iterator', 'match', 'replace', 'search', 'split', 'hasInstance', 'isConcatSpreadable', 'unscopables', 'species', 'toPrimitive', toStringTag].forEach(function (name) {
+        if (!(name in Symbol)) {
+          dP(Symbol, name, { value: Symbol(name) });
+          switch (name) {
+            case toStringTag:
+              descriptor = O.getOwnPropertyDescriptor(ObjectProto, 'toString');
+              descriptor.value = function () {
+                var str = toString.call(this),
+                    tst = typeof this === 'undefined' || this === null ? undefined : this[Symbol.toStringTag];
+                return typeof tst === 'undefined' ? str : '[object ' + tst + ']';
+              };
+              dP(ObjectProto, 'toString', descriptor);
+              break;
+          }
         }
+      });
+    })(Object, Symbol);
+
+    (function (Si, AP, SP) {
+
+      function returnThis() {
+        return this;
+      }
+
+      if (!AP[Si]) AP[Si] = function () {
+        var i = 0,
+            self = this,
+            iterator = {
+          next: function next() {
+            var done = self.length <= i;
+            return done ? { done: done } : { done: done, value: self[i++] };
+          }
+        };
+        iterator[Si] = returnThis;
+        return iterator;
       };
-      iterator[Si] = returnThis;
-      return iterator;
-    };
 
-    if (!SP[Si]) SP[Si] = function () {
-      var fromCodePoint = String.fromCodePoint,
-          self = this,
-          i = 0,
-          length = self.length,
-          iterator = {
-        next: function next() {
-          var done = length <= i,
-              c = done ? '' : fromCodePoint(self.codePointAt(i));
-          i += c.length;
-          return done ? { done: done } : { done: done, value: c };
-        }
+      if (!SP[Si]) SP[Si] = function () {
+        var fromCodePoint = String.fromCodePoint,
+            self = this,
+            i = 0,
+            length = self.length,
+            iterator = {
+          next: function next() {
+            var done = length <= i,
+                c = done ? '' : fromCodePoint(self.codePointAt(i));
+            i += c.length;
+            return done ? { done: done } : { done: done, value: c };
+          }
+        };
+        iterator[Si] = returnThis;
+        return iterator;
       };
-      iterator[Si] = returnThis;
-      return iterator;
+    })(Symbol.iterator, Array.prototype, String.prototype);
+  }
+
+  if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
+    Number.isNaN = Number.isNaN || function (value) {
+      return value !== value;
     };
-  })(Symbol.iterator, Array.prototype, String.prototype);
 
-  Number.isNaN = Number.isNaN || function (value) {
-    return value !== value;
-  };
+    Number.isFinite = Number.isFinite || function (value) {
+      return typeof value === "number" && isFinite(value);
+    };
+  }
 
-  Number.isFinite = Number.isFinite || function (value) {
-    return typeof value === "number" && isFinite(value);
-  };
   if (!String.prototype.endsWith || function () {
     try {
       return !"ab".endsWith("a", 1);
@@ -298,109 +305,112 @@ define(['aurelia-pal'], function (_aureliaPal) {
     };
   }
 
-  if (!Array.from) {
-    Array.from = function () {
-      var toInteger = function toInteger(it) {
-        return isNaN(it = +it) ? 0 : (it > 0 ? Math.floor : Math.ceil)(it);
-      };
-      var toLength = function toLength(it) {
-        return it > 0 ? Math.min(toInteger(it), 0x1fffffffffffff) : 0;
-      };
-      var iterCall = function iterCall(iter, fn, val, index) {
-        try {
-          return fn(val, index);
-        } catch (E) {
-          if (typeof iter.return == 'function') iter.return();
-          throw E;
-        }
-      };
+  if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-      return function from(arrayLike) {
-        var O = Object(arrayLike),
-            C = typeof this == 'function' ? this : Array,
-            aLen = arguments.length,
-            mapfn = aLen > 1 ? arguments[1] : undefined,
-            mapping = mapfn !== undefined,
-            index = 0,
-            iterFn = O[Symbol.iterator],
-            length,
-            result,
-            step,
-            iterator;
-        if (mapping) mapfn = mapfn.bind(aLen > 2 ? arguments[2] : undefined);
-        if (iterFn != undefined && !Array.isArray(arrayLike)) {
-          for (iterator = iterFn.call(O), result = new C(); !(step = iterator.next()).done; index++) {
-            result[index] = mapping ? iterCall(iterator, mapfn, step.value, index) : step.value;
+    if (!Array.from) {
+      Array.from = function () {
+        var toInteger = function toInteger(it) {
+          return isNaN(it = +it) ? 0 : (it > 0 ? Math.floor : Math.ceil)(it);
+        };
+        var toLength = function toLength(it) {
+          return it > 0 ? Math.min(toInteger(it), 0x1fffffffffffff) : 0;
+        };
+        var iterCall = function iterCall(iter, fn, val, index) {
+          try {
+            return fn(val, index);
+          } catch (E) {
+            if (typeof iter.return == 'function') iter.return();
+            throw E;
           }
-        } else {
-          length = toLength(O.length);
-          for (result = new C(length); length > index; index++) {
-            result[index] = mapping ? mapfn(O[index], index) : O[index];
+        };
+
+        return function from(arrayLike) {
+          var O = Object(arrayLike),
+              C = typeof this == 'function' ? this : Array,
+              aLen = arguments.length,
+              mapfn = aLen > 1 ? arguments[1] : undefined,
+              mapping = mapfn !== undefined,
+              index = 0,
+              iterFn = O[Symbol.iterator],
+              length,
+              result,
+              step,
+              iterator;
+          if (mapping) mapfn = mapfn.bind(aLen > 2 ? arguments[2] : undefined);
+          if (iterFn != undefined && !Array.isArray(arrayLike)) {
+            for (iterator = iterFn.call(O), result = new C(); !(step = iterator.next()).done; index++) {
+              result[index] = mapping ? iterCall(iterator, mapfn, step.value, index) : step.value;
+            }
+          } else {
+            length = toLength(O.length);
+            for (result = new C(length); length > index; index++) {
+              result[index] = mapping ? mapfn(O[index], index) : O[index];
+            }
           }
-        }
-        result.length = index;
-        return result;
-      };
-    }();
-  }
+          result.length = index;
+          return result;
+        };
+      }();
+    }
 
-  if (!Array.prototype.find) {
-    Object.defineProperty(Array.prototype, 'find', {
-      configurable: true,
-      writable: true,
-      enumerable: false,
-      value: function value(predicate) {
-        if (this === null) {
-          throw new TypeError('Array.prototype.find called on null or undefined');
-        }
-        if (typeof predicate !== 'function') {
-          throw new TypeError('predicate must be a function');
-        }
-        var list = Object(this);
-        var length = list.length >>> 0;
-        var thisArg = arguments[1];
-        var value;
-
-        for (var i = 0; i < length; i++) {
-          value = list[i];
-          if (predicate.call(thisArg, value, i, list)) {
-            return value;
+    if (!Array.prototype.find) {
+      Object.defineProperty(Array.prototype, 'find', {
+        configurable: true,
+        writable: true,
+        enumerable: false,
+        value: function value(predicate) {
+          if (this === null) {
+            throw new TypeError('Array.prototype.find called on null or undefined');
+          }
+          if (typeof predicate !== 'function') {
+            throw new TypeError('predicate must be a function');
+          }
+          var list = Object(this);
+          var length = list.length >>> 0;
+          var thisArg = arguments[1];
+          var value;
+
+          for (var i = 0; i < length; i++) {
+            value = list[i];
+            if (predicate.call(thisArg, value, i, list)) {
+              return value;
+            }
           }
+          return undefined;
         }
-        return undefined;
-      }
-    });
-  }
+      });
+    }
 
-  if (!Array.prototype.findIndex) {
-    Object.defineProperty(Array.prototype, 'findIndex', {
-      configurable: true,
-      writable: true,
-      enumerable: false,
-      value: function value(predicate) {
-        if (this === null) {
-          throw new TypeError('Array.prototype.findIndex called on null or undefined');
-        }
-        if (typeof predicate !== 'function') {
-          throw new TypeError('predicate must be a function');
-        }
-        var list = Object(this);
-        var length = list.length >>> 0;
-        var thisArg = arguments[1];
-        var value;
-
-        for (var i = 0; i < length; i++) {
-          value = list[i];
-          if (predicate.call(thisArg, value, i, list)) {
-            return i;
+    if (!Array.prototype.findIndex) {
+      Object.defineProperty(Array.prototype, 'findIndex', {
+        configurable: true,
+        writable: true,
+        enumerable: false,
+        value: function value(predicate) {
+          if (this === null) {
+            throw new TypeError('Array.prototype.findIndex called on null or undefined');
+          }
+          if (typeof predicate !== 'function') {
+            throw new TypeError('predicate must be a function');
+          }
+          var list = Object(this);
+          var length = list.length >>> 0;
+          var thisArg = arguments[1];
+          var value;
+
+          for (var i = 0; i < length; i++) {
+            value = list[i];
+            if (predicate.call(thisArg, value, i, list)) {
+              return i;
+            }
           }
+          return -1;
         }
-        return -1;
-      }
-    });
+      });
+    }
   }
 
-  if (!Array.prototype.includes) {
+  if (typeof FEATURE_NO_ES2016 === 'undefined' && !Array.prototype.includes) {
     Object.defineProperty(Array.prototype, 'includes', {
       configurable: true,
       writable: true,
@@ -434,376 +444,393 @@ define(['aurelia-pal'], function (_aureliaPal) {
     });
   }
 
-  (function () {
-    var needsFix = false;
+  if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-    try {
-      var s = Object.keys('a');
-      needsFix = s.length !== 1 || s[0] !== '0';
-    } catch (e) {
-      needsFix = true;
-    }
+    (function () {
+      var needsFix = false;
 
-    if (needsFix) {
-      Object.keys = function () {
-        var hasOwnProperty = Object.prototype.hasOwnProperty,
-            hasDontEnumBug = !{ toString: null }.propertyIsEnumerable('toString'),
-            dontEnums = ['toString', 'toLocaleString', 'valueOf', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable', 'constructor'],
-            dontEnumsLength = dontEnums.length;
+      try {
+        var s = Object.keys('a');
+        needsFix = s.length !== 1 || s[0] !== '0';
+      } catch (e) {
+        needsFix = true;
+      }
 
-        return function (obj) {
-          if (obj === undefined || obj === null) {
-            throw TypeError('Cannot convert undefined or null to object');
-          }
+      if (needsFix) {
+        Object.keys = function () {
+          var hasOwnProperty = Object.prototype.hasOwnProperty,
+              hasDontEnumBug = !{ toString: null }.propertyIsEnumerable('toString'),
+              dontEnums = ['toString', 'toLocaleString', 'valueOf', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable', 'constructor'],
+              dontEnumsLength = dontEnums.length;
 
-          obj = Object(obj);
+          return function (obj) {
+            if (obj === undefined || obj === null) {
+              throw TypeError('Cannot convert undefined or null to object');
+            }
+
+            obj = Object(obj);
 
-          var result = [],
-              prop,
-              i;
+            var result = [],
+                prop,
+                i;
 
-          for (prop in obj) {
-            if (hasOwnProperty.call(obj, prop)) {
-              result.push(prop);
+            for (prop in obj) {
+              if (hasOwnProperty.call(obj, prop)) {
+                result.push(prop);
+              }
             }
-          }
 
-          if (hasDontEnumBug) {
-            for (i = 0; i < dontEnumsLength; i++) {
-              if (hasOwnProperty.call(obj, dontEnums[i])) {
-                result.push(dontEnums[i]);
+            if (hasDontEnumBug) {
+              for (i = 0; i < dontEnumsLength; i++) {
+                if (hasOwnProperty.call(obj, dontEnums[i])) {
+                  result.push(dontEnums[i]);
+                }
               }
             }
-          }
 
-          return result;
-        };
-      }();
-    }
-  })();
+            return result;
+          };
+        }();
+      }
+    })();
 
-  (function (O) {
-    if ('assign' in O) {
-      return;
-    }
+    (function (O) {
+      if ('assign' in O) {
+        return;
+      }
 
-    O.defineProperty(O, 'assign', {
-      configurable: true,
-      writable: true,
-      value: function () {
-        var gOPS = O.getOwnPropertySymbols,
-            pIE = O.propertyIsEnumerable,
-            filterOS = gOPS ? function (self) {
-          return gOPS(self).filter(pIE, self);
-        } : function () {
-          return Array.prototype;
-        };
+      O.defineProperty(O, 'assign', {
+        configurable: true,
+        writable: true,
+        value: function () {
+          var gOPS = O.getOwnPropertySymbols,
+              pIE = O.propertyIsEnumerable,
+              filterOS = gOPS ? function (self) {
+            return gOPS(self).filter(pIE, self);
+          } : function () {
+            return Array.prototype;
+          };
+
+          return function assign(where) {
+            if (gOPS && !(where instanceof O)) {
+              console.warn('problematic Symbols', where);
+            }
 
-        return function assign(where) {
-          if (gOPS && !(where instanceof O)) {
-            console.warn('problematic Symbols', where);
-          }
+            function set(keyOrSymbol) {
+              where[keyOrSymbol] = arg[keyOrSymbol];
+            }
 
-          function set(keyOrSymbol) {
-            where[keyOrSymbol] = arg[keyOrSymbol];
-          }
+            for (var i = 1, ii = arguments.length; i < ii; ++i) {
+              var arg = arguments[i];
 
-          for (var i = 1, ii = arguments.length; i < ii; ++i) {
-            var arg = arguments[i];
+              if (arg === null || arg === undefined) {
+                continue;
+              }
 
-            if (arg === null || arg === undefined) {
-              continue;
+              O.keys(arg).concat(filterOS(arg)).forEach(set);
             }
 
-            O.keys(arg).concat(filterOS(arg)).forEach(set);
-          }
-
-          return where;
-        };
-      }()
-    });
-  })(Object);
+            return where;
+          };
+        }()
+      });
+    })(Object);
+  }
 
-  (function (global) {
-    var i;
+  if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-    var defineProperty = Object.defineProperty,
-        is = function is(a, b) {
-      return a === b || a !== a && b !== b;
-    };
+    (function (global) {
+      var i;
 
-    if (typeof WeakMap == 'undefined') {
-      global.WeakMap = createCollection({
-        'delete': sharedDelete,
+      var defineProperty = Object.defineProperty,
+          is = function is(a, b) {
+        return a === b || a !== a && b !== b;
+      };
 
-        clear: sharedClear,
+      if (typeof WeakMap == 'undefined') {
+        global.WeakMap = createCollection({
+          'delete': sharedDelete,
 
-        get: sharedGet,
+          clear: sharedClear,
 
-        has: mapHas,
+          get: sharedGet,
 
-        set: sharedSet
-      }, true);
-    }
+          has: mapHas,
 
-    if (typeof Map == 'undefined' || typeof new Map().values !== 'function' || !new Map().values().next) {
-      var _createCollection;
-
-      global.Map = createCollection((_createCollection = {
-        'delete': sharedDelete,
+          set: sharedSet
+        }, true);
+      }
 
-        has: mapHas,
+      if (typeof Map == 'undefined' || typeof new Map().values !== 'function' || !new Map().values().next) {
+        var _createCollection;
 
-        get: sharedGet,
+        global.Map = createCollection((_createCollection = {
+          'delete': sharedDelete,
 
-        set: sharedSet,
+          has: mapHas,
 
-        keys: sharedKeys,
+          get: sharedGet,
 
-        values: sharedValues,
+          set: sharedSet,
 
-        entries: mapEntries,
+          keys: sharedKeys,
 
-        forEach: sharedForEach,
+          values: sharedValues,
 
-        clear: sharedClear
-      }, _createCollection[Symbol.iterator] = mapEntries, _createCollection));
-    }
+          entries: mapEntries,
 
-    if (typeof Set == 'undefined' || typeof new Set().values !== 'function' || !new Set().values().next) {
-      var _createCollection2;
+          forEach: sharedForEach,
 
-      global.Set = createCollection((_createCollection2 = {
-        has: setHas,
+          clear: sharedClear
+        }, _createCollection[Symbol.iterator] = mapEntries, _createCollection));
+      }
 
-        add: sharedAdd,
+      if (typeof Set == 'undefined' || typeof new Set().values !== 'function' || !new Set().values().next) {
+        var _createCollection2;
 
-        'delete': sharedDelete,
+        global.Set = createCollection((_createCollection2 = {
+          has: setHas,
 
-        clear: sharedClear,
+          add: sharedAdd,
 
-        keys: sharedValues,
-        values: sharedValues,
+          'delete': sharedDelete,
 
-        entries: setEntries,
+          clear: sharedClear,
 
-        forEach: sharedForEach
-      }, _createCollection2[Symbol.iterator] = sharedValues, _createCollection2));
-    }
+          keys: sharedValues,
+          values: sharedValues,
 
-    if (typeof WeakSet == 'undefined') {
-      global.WeakSet = createCollection({
-        'delete': sharedDelete,
+          entries: setEntries,
 
-        add: sharedAdd,
+          forEach: sharedForEach
+        }, _createCollection2[Symbol.iterator] = sharedValues, _createCollection2));
+      }
 
-        clear: sharedClear,
+      if (typeof WeakSet == 'undefined') {
+        global.WeakSet = createCollection({
+          'delete': sharedDelete,
 
-        has: setHas
-      }, true);
-    }
+          add: sharedAdd,
 
-    function createCollection(proto, objectOnly) {
-      function Collection(a) {
-        if (!this || this.constructor !== Collection) return new Collection(a);
-        this._keys = [];
-        this._values = [];
-        this._itp = [];
-        this.objectOnly = objectOnly;
+          clear: sharedClear,
 
-        if (a) init.call(this, a);
+          has: setHas
+        }, true);
       }
 
-      if (!objectOnly) {
-        defineProperty(proto, 'size', {
-          get: sharedSize
-        });
-      }
+      function createCollection(proto, objectOnly) {
+        function Collection(a) {
+          if (!this || this.constructor !== Collection) return new Collection(a);
+          this._keys = [];
+          this._values = [];
+          this._itp = [];
+          this.objectOnly = objectOnly;
 
-      proto.constructor = Collection;
-      Collection.prototype = proto;
+          if (a) init.call(this, a);
+        }
 
-      return Collection;
-    }
+        if (!objectOnly) {
+          defineProperty(proto, 'size', {
+            get: sharedSize
+          });
+        }
 
-    function init(a) {
-      var i;
+        proto.constructor = Collection;
+        Collection.prototype = proto;
 
-      if (this.add) a.forEach(this.add, this);else a.forEach(function (a) {
-          this.set(a[0], a[1]);
-        }, this);
-    }
+        return Collection;
+      }
 
-    function sharedDelete(key) {
-      if (this.has(key)) {
-        this._keys.splice(i, 1);
-        this._values.splice(i, 1);
+      function init(a) {
+        var i;
 
-        this._itp.forEach(function (p) {
-          if (i < p[0]) p[0]--;
-        });
+        if (this.add) a.forEach(this.add, this);else a.forEach(function (a) {
+            this.set(a[0], a[1]);
+          }, this);
       }
 
-      return -1 < i;
-    };
-
-    function sharedGet(key) {
-      return this.has(key) ? this._values[i] : undefined;
-    }
+      function sharedDelete(key) {
+        if (this.has(key)) {
+          this._keys.splice(i, 1);
+          this._values.splice(i, 1);
 
-    function has(list, key) {
-      if (this.objectOnly && key !== Object(key)) throw new TypeError("Invalid value used as weak collection key");
+          this._itp.forEach(function (p) {
+            if (i < p[0]) p[0]--;
+          });
+        }
 
-      if (key != key || key === 0) for (i = list.length; i-- && !is(list[i], key);) {} else i = list.indexOf(key);
-      return -1 < i;
-    }
+        return -1 < i;
+      };
 
-    function setHas(value) {
-      return has.call(this, this._values, value);
-    }
+      function sharedGet(key) {
+        return this.has(key) ? this._values[i] : undefined;
+      }
 
-    function mapHas(value) {
-      return has.call(this, this._keys, value);
-    }
+      function has(list, key) {
+        if (this.objectOnly && key !== Object(key)) throw new TypeError("Invalid value used as weak collection key");
 
-    function sharedSet(key, value) {
-      this.has(key) ? this._values[i] = value : this._values[this._keys.push(key) - 1] = value;
-      return this;
-    }
+        if (key != key || key === 0) for (i = list.length; i-- && !is(list[i], key);) {} else i = list.indexOf(key);
+        return -1 < i;
+      }
 
-    function sharedAdd(value) {
-      if (!this.has(value)) this._values.push(value);
-      return this;
-    }
+      function setHas(value) {
+        return has.call(this, this._values, value);
+      }
 
-    function sharedClear() {
-      (this._keys || 0).length = this._values.length = 0;
-    }
+      function mapHas(value) {
+        return has.call(this, this._keys, value);
+      }
 
-    function sharedKeys() {
-      return sharedIterator(this._itp, this._keys);
-    }
+      function sharedSet(key, value) {
+        this.has(key) ? this._values[i] = value : this._values[this._keys.push(key) - 1] = value;
+        return this;
+      }
 
-    function sharedValues() {
-      return sharedIterator(this._itp, this._values);
-    }
+      function sharedAdd(value) {
+        if (!this.has(value)) this._values.push(value);
+        return this;
+      }
 
-    function mapEntries() {
-      return sharedIterator(this._itp, this._keys, this._values);
-    }
+      function sharedClear() {
+        (this._keys || 0).length = this._values.length = 0;
+      }
 
-    function setEntries() {
-      return sharedIterator(this._itp, this._values, this._values);
-    }
+      function sharedKeys() {
+        return sharedIterator(this._itp, this._keys);
+      }
 
-    function sharedIterator(itp, array, array2) {
-      var _ref;
+      function sharedValues() {
+        return sharedIterator(this._itp, this._values);
+      }
 
-      var p = [0],
-          done = false;
-      itp.push(p);
-      return _ref = {}, _ref[Symbol.iterator] = function () {
-        return this;
-      }, _ref.next = function next() {
-        var v,
-            k = p[0];
-        if (!done && k < array.length) {
-          v = array2 ? [array[k], array2[k]] : array[k];
-          p[0]++;
-        } else {
-          done = true;
-          itp.splice(itp.indexOf(p), 1);
-        }
-        return { done: done, value: v };
-      }, _ref;
-    }
+      function mapEntries() {
+        return sharedIterator(this._itp, this._keys, this._values);
+      }
 
-    function sharedSize() {
-      return this._values.length;
-    }
+      function setEntries() {
+        return sharedIterator(this._itp, this._values, this._values);
+      }
 
-    function sharedForEach(callback, context) {
-      var it = this.entries();
-      for (;;) {
-        var r = it.next();
-        if (r.done) break;
-        callback.call(context, r.value[1], r.value[0], this);
+      function sharedIterator(itp, array, array2) {
+        var _ref;
+
+        var p = [0],
+            done = false;
+        itp.push(p);
+        return _ref = {}, _ref[Symbol.iterator] = function () {
+          return this;
+        }, _ref.next = function next() {
+          var v,
+              k = p[0];
+          if (!done && k < array.length) {
+            v = array2 ? [array[k], array2[k]] : array[k];
+            p[0]++;
+          } else {
+            done = true;
+            itp.splice(itp.indexOf(p), 1);
+          }
+          return { done: done, value: v };
+        }, _ref;
       }
-    }
-  })(_aureliaPal.PLATFORM.global);
 
-  var emptyMetadata = Object.freeze({});
-  var metadataContainerKey = '__metadata__';
-  var bind = Function.prototype.bind;
+      function sharedSize() {
+        return this._values.length;
+      }
 
-  if (typeof _aureliaPal.PLATFORM.global.Reflect === 'undefined') {
-    _aureliaPal.PLATFORM.global.Reflect = {};
+      function sharedForEach(callback, context) {
+        var it = this.entries();
+        for (;;) {
+          var r = it.next();
+          if (r.done) break;
+          callback.call(context, r.value[1], r.value[0], this);
+        }
+      }
+    })(_aureliaPal.PLATFORM.global);
   }
 
-  if (typeof Reflect.getOwnMetadata !== 'function') {
-    Reflect.getOwnMetadata = function (metadataKey, target, targetKey) {
-      if (target.hasOwnProperty(metadataContainerKey)) {
-        return (target[metadataContainerKey][targetKey] || emptyMetadata)[metadataKey];
+  if (typeof FEATURE_NO_ES2015 === 'undefined') {
+    (function () {
+
+      var bind = Function.prototype.bind;
+
+      if (typeof _aureliaPal.PLATFORM.global.Reflect === 'undefined') {
+        _aureliaPal.PLATFORM.global.Reflect = {};
       }
-    };
-  }
 
-  if (typeof Reflect.defineMetadata !== 'function') {
-    Reflect.defineMetadata = function (metadataKey, metadataValue, target, targetKey) {
-      var metadataContainer = target.hasOwnProperty(metadataContainerKey) ? target[metadataContainerKey] : target[metadataContainerKey] = {};
-      var targetContainer = metadataContainer[targetKey] || (metadataContainer[targetKey] = {});
-      targetContainer[metadataKey] = metadataValue;
-    };
-  }
+      if (typeof Reflect.defineProperty !== 'function') {
+        Reflect.defineProperty = function (target, propertyKey, descriptor) {
+          if ((typeof target === 'undefined' ? 'undefined' : _typeof(target)) === 'object' ? target === null : typeof target !== 'function') {
+            throw new TypeError('Reflect.defineProperty called on non-object');
+          }
+          try {
+            Object.defineProperty(target, propertyKey, descriptor);
+            return true;
+          } catch (e) {
+            return false;
+          }
+        };
+      }
 
-  if (typeof Reflect.metadata !== 'function') {
-    Reflect.metadata = function (metadataKey, metadataValue) {
-      return function (target, targetKey) {
-        Reflect.defineMetadata(metadataKey, metadataValue, target, targetKey);
-      };
-    };
-  }
+      if (typeof Reflect.construct !== 'function') {
+        Reflect.construct = function (Target, args) {
+          if (args) {
+            switch (args.length) {
+              case 0:
+                return new Target();
+              case 1:
+                return new Target(args[0]);
+              case 2:
+                return new Target(args[0], args[1]);
+              case 3:
+                return new Target(args[0], args[1], args[2]);
+              case 4:
+                return new Target(args[0], args[1], args[2], args[3]);
+            }
+          }
 
-  if (typeof Reflect.defineProperty !== 'function') {
-    Reflect.defineProperty = function (target, propertyKey, descriptor) {
-      if ((typeof target === 'undefined' ? 'undefined' : _typeof(target)) === 'object' ? target === null : typeof target !== 'function') {
-        throw new TypeError('Reflect.defineProperty called on non-object');
+          var a = [null];
+          a.push.apply(a, args);
+          return new (bind.apply(Target, a))();
+        };
       }
-      try {
-        Object.defineProperty(target, propertyKey, descriptor);
-        return true;
-      } catch (e) {
-        return false;
+
+      if (typeof Reflect.ownKeys !== 'function') {
+        Reflect.ownKeys = function (o) {
+          return Object.getOwnPropertyNames(o).concat(Object.getOwnPropertySymbols(o));
+        };
       }
-    };
+    })();
   }
 
-  if (typeof Reflect.construct !== 'function') {
-    Reflect.construct = function (Target, args) {
-      if (args) {
-        switch (args.length) {
-          case 0:
-            return new Target();
-          case 1:
-            return new Target(args[0]);
-          case 2:
-            return new Target(args[0], args[1]);
-          case 3:
-            return new Target(args[0], args[1], args[2]);
-          case 4:
-            return new Target(args[0], args[1], args[2], args[3]);
-        }
+  if (typeof FEATURE_NO_ESNEXT === 'undefined') {
+    (function () {
+
+      var emptyMetadata = Object.freeze({});
+      var metadataContainerKey = '__metadata__';
+
+      if (typeof Reflect.getOwnMetadata !== 'function') {
+        Reflect.getOwnMetadata = function (metadataKey, target, targetKey) {
+          if (target.hasOwnProperty(metadataContainerKey)) {
+            return (target[metadataContainerKey][targetKey] || emptyMetadata)[metadataKey];
+          }
+        };
       }
 
-      var a = [null];
-      a.push.apply(a, args);
-      return new (bind.apply(Target, a))();
-    };
-  }
+      if (typeof Reflect.defineMetadata !== 'function') {
+        Reflect.defineMetadata = function (metadataKey, metadataValue, target, targetKey) {
+          var metadataContainer = target.hasOwnProperty(metadataContainerKey) ? target[metadataContainerKey] : target[metadataContainerKey] = {};
+          var targetContainer = metadataContainer[targetKey] || (metadataContainer[targetKey] = {});
+          targetContainer[metadataKey] = metadataValue;
+        };
+      }
 
-  if (typeof Reflect.ownKeys !== 'function') {
-    Reflect.ownKeys = function (o) {
-      return Object.getOwnPropertyNames(o).concat(Object.getOwnPropertySymbols(o));
-    };
+      if (typeof Reflect.metadata !== 'function') {
+        Reflect.metadata = function (metadataKey, metadataValue) {
+          return function (target, targetKey) {
+            Reflect.defineMetadata(metadataKey, metadataValue, target, targetKey);
+          };
+        };
+      }
+    })();
   }
 });
\ No newline at end of file
diff --git a/dist/aurelia-polyfills.js b/dist/aurelia-polyfills.js
index 84a1d18..36ce1a6 100644
--- a/dist/aurelia-polyfills.js
+++ b/dist/aurelia-polyfills.js
@@ -1,5 +1,7 @@
 import {PLATFORM} from 'aurelia-pal';
 
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
 (function (Object, GOPS) {'use strict';
 
   // (C) Andrea Giammarchi - Mit Style
@@ -311,6 +313,11 @@ import {PLATFORM} from 'aurelia-pal';
 
 }(Symbol.iterator, Array.prototype, String.prototype));
 
+
+} // endif FEATURE_NO_ES2015
+
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
 Number.isNaN = Number.isNaN || function(value) {     
   return value !== value;
 };
@@ -318,6 +325,9 @@ Number.isNaN = Number.isNaN || function(value) {
 Number.isFinite = Number.isFinite || function(value) {
   return typeof value === "number" && isFinite(value);
 };
+
+} // endif FEATURE_NO_ES2015
+
 if ((!String.prototype.endsWith) || ((function() { try { return !("ab".endsWith("a",1)); } catch (e) { return true; } } )())) {
   String.prototype.endsWith = function(searchString, position) {
     let subjectString = this.toString();
@@ -337,6 +347,8 @@ if ((!String.prototype.startsWith) || ((function() { try { return !("ab".startsW
   };
 }
 
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
 if (!Array.from) {
   Array.from = (function () {
     var toInteger = function(it) {
@@ -438,7 +450,9 @@ if (!Array.prototype.findIndex) {
   });
 }
 
-if (!Array.prototype.includes) {
+} // endif FEATURE_NO_ES2015
+
+if (typeof FEATURE_NO_ES2016 === 'undefined' && !Array.prototype.includes) {
   Object.defineProperty(Array.prototype, 'includes', {
     configurable: true,
     writable: true,
@@ -471,6 +485,8 @@ if (!Array.prototype.includes) {
   });
 }
 
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
 (function() {
   let needsFix = false;
 
@@ -577,6 +593,10 @@ if (!Array.prototype.includes) {
     });
 }(Object));
 
+} // endif FEATURE_NO_ES2015
+
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+  
 (function (global) {
   //shared pointer
   var i;
@@ -811,38 +831,16 @@ if (!Array.prototype.includes) {
 
 })(PLATFORM.global);
 
-const emptyMetadata = Object.freeze({});
-const metadataContainerKey = '__metadata__';
+} // endif (FEATURE_NO_ES2015)
+
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
 const bind = Function.prototype.bind;
 
 if (typeof PLATFORM.global.Reflect === 'undefined') {
   PLATFORM.global.Reflect = {};
 }
 
-if (typeof Reflect.getOwnMetadata !== 'function') {
-  Reflect.getOwnMetadata = function(metadataKey, target, targetKey) {
-    if (target.hasOwnProperty(metadataContainerKey)) {
-      return (target[metadataContainerKey][targetKey] || emptyMetadata)[metadataKey];
-    }
-  };
-}
-
-if (typeof Reflect.defineMetadata !== 'function') {
-  Reflect.defineMetadata = function(metadataKey, metadataValue, target, targetKey) {
-    let metadataContainer = target.hasOwnProperty(metadataContainerKey) ? target[metadataContainerKey] : (target[metadataContainerKey] = {});
-    let targetContainer = metadataContainer[targetKey] || (metadataContainer[targetKey] = {});
-    targetContainer[metadataKey] = metadataValue;
-  };
-}
-
-if (typeof Reflect.metadata !== 'function') {
-  Reflect.metadata = function(metadataKey, metadataValue) {
-    return function(target, targetKey) {
-      Reflect.defineMetadata(metadataKey, metadataValue, target, targetKey);
-    };
-  };
-}
-
 if (typeof Reflect.defineProperty !== 'function') {
   Reflect.defineProperty = function(target, propertyKey, descriptor) {
     if (typeof target === 'object' ? target === null : typeof target !== 'function') {
@@ -878,3 +876,36 @@ if (typeof Reflect.construct !== 'function') {
 if (typeof Reflect.ownKeys !== 'function') {
   Reflect.ownKeys = function(o) { return (Object.getOwnPropertyNames(o).concat(Object.getOwnPropertySymbols(o))); }
 }
+
+} // endif FEATURE_NO_ES2015
+
+if (typeof FEATURE_NO_ESNEXT === 'undefined') {
+
+const emptyMetadata = Object.freeze({});
+const metadataContainerKey = '__metadata__';
+
+if (typeof Reflect.getOwnMetadata !== 'function') {
+  Reflect.getOwnMetadata = function(metadataKey, target, targetKey) {
+    if (target.hasOwnProperty(metadataContainerKey)) {
+      return (target[metadataContainerKey][targetKey] || emptyMetadata)[metadataKey];
+    }
+  };
+}
+
+if (typeof Reflect.defineMetadata !== 'function') {
+  Reflect.defineMetadata = function(metadataKey, metadataValue, target, targetKey) {
+    let metadataContainer = target.hasOwnProperty(metadataContainerKey) ? target[metadataContainerKey] : (target[metadataContainerKey] = {});
+    let targetContainer = metadataContainer[targetKey] || (metadataContainer[targetKey] = {});
+    targetContainer[metadataKey] = metadataValue;
+  };
+}
+
+if (typeof Reflect.metadata !== 'function') {
+  Reflect.metadata = function(metadataKey, metadataValue) {
+    return function(target, targetKey) {
+      Reflect.defineMetadata(metadataKey, metadataValue, target, targetKey);
+    };
+  };
+}
+
+} // endif FEATURE_NO_ESNEXT
diff --git a/dist/commonjs/aurelia-polyfills.js b/dist/commonjs/aurelia-polyfills.js
index c9a6acc..456f840 100644
--- a/dist/commonjs/aurelia-polyfills.js
+++ b/dist/commonjs/aurelia-polyfills.js
@@ -4,266 +4,273 @@ var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol
 
 var _aureliaPal = require('aurelia-pal');
 
-(function (Object, GOPS) {
-  'use strict';
-
-  if (GOPS in Object) return;
-
-  var setDescriptor,
-      G = _aureliaPal.PLATFORM.global,
-      id = 0,
-      random = '' + Math.random(),
-      prefix = '__\x01symbol:',
-      prefixLength = prefix.length,
-      internalSymbol = '__\x01symbol@@' + random,
-      DP = 'defineProperty',
-      DPies = 'defineProperties',
-      GOPN = 'getOwnPropertyNames',
-      GOPD = 'getOwnPropertyDescriptor',
-      PIE = 'propertyIsEnumerable',
-      gOPN = Object[GOPN],
-      gOPD = Object[GOPD],
-      create = Object.create,
-      keys = Object.keys,
-      defineProperty = Object[DP],
-      $defineProperties = Object[DPies],
-      descriptor = gOPD(Object, GOPN),
-      ObjectProto = Object.prototype,
-      hOP = ObjectProto.hasOwnProperty,
-      pIE = ObjectProto[PIE],
-      toString = ObjectProto.toString,
-      indexOf = Array.prototype.indexOf || function (v) {
-    for (var i = this.length; i-- && this[i] !== v;) {}
-    return i;
-  },
-      addInternalIfNeeded = function addInternalIfNeeded(o, uid, enumerable) {
-    if (!hOP.call(o, internalSymbol)) {
-      defineProperty(o, internalSymbol, {
-        enumerable: false,
-        configurable: false,
-        writable: false,
-        value: {}
-      });
-    }
-    o[internalSymbol]['@@' + uid] = enumerable;
-  },
-      createWithSymbols = function createWithSymbols(proto, descriptors) {
-    var self = create(proto);
-    gOPN(descriptors).forEach(function (key) {
-      if (propertyIsEnumerable.call(descriptors, key)) {
-        $defineProperty(self, key, descriptors[key]);
-      }
-    });
-    return self;
-  },
-      copyAsNonEnumerable = function copyAsNonEnumerable(descriptor) {
-    var newDescriptor = create(descriptor);
-    newDescriptor.enumerable = false;
-    return newDescriptor;
-  },
-      get = function get() {},
-      onlyNonSymbols = function onlyNonSymbols(name) {
-    return name != internalSymbol && !hOP.call(source, name);
-  },
-      onlySymbols = function onlySymbols(name) {
-    return name != internalSymbol && hOP.call(source, name);
-  },
-      propertyIsEnumerable = function propertyIsEnumerable(key) {
-    var uid = '' + key;
-    return onlySymbols(uid) ? hOP.call(this, uid) && this[internalSymbol]['@@' + uid] : pIE.call(this, key);
-  },
-      setAndGetSymbol = function setAndGetSymbol(uid) {
-    var descriptor = {
-      enumerable: false,
-      configurable: true,
-      get: get,
-      set: function set(value) {
-        setDescriptor(this, uid, {
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
+  (function (Object, GOPS) {
+    'use strict';
+
+    if (GOPS in Object) return;
+
+    var setDescriptor,
+        G = _aureliaPal.PLATFORM.global,
+        id = 0,
+        random = '' + Math.random(),
+        prefix = '__\x01symbol:',
+        prefixLength = prefix.length,
+        internalSymbol = '__\x01symbol@@' + random,
+        DP = 'defineProperty',
+        DPies = 'defineProperties',
+        GOPN = 'getOwnPropertyNames',
+        GOPD = 'getOwnPropertyDescriptor',
+        PIE = 'propertyIsEnumerable',
+        gOPN = Object[GOPN],
+        gOPD = Object[GOPD],
+        create = Object.create,
+        keys = Object.keys,
+        defineProperty = Object[DP],
+        $defineProperties = Object[DPies],
+        descriptor = gOPD(Object, GOPN),
+        ObjectProto = Object.prototype,
+        hOP = ObjectProto.hasOwnProperty,
+        pIE = ObjectProto[PIE],
+        toString = ObjectProto.toString,
+        indexOf = Array.prototype.indexOf || function (v) {
+      for (var i = this.length; i-- && this[i] !== v;) {}
+      return i;
+    },
+        addInternalIfNeeded = function addInternalIfNeeded(o, uid, enumerable) {
+      if (!hOP.call(o, internalSymbol)) {
+        defineProperty(o, internalSymbol, {
           enumerable: false,
-          configurable: true,
-          writable: true,
-          value: value
+          configurable: false,
+          writable: false,
+          value: {}
         });
-        addInternalIfNeeded(this, uid, true);
       }
-    };
-    defineProperty(ObjectProto, uid, descriptor);
-    return source[uid] = defineProperty(Object(uid), 'constructor', sourceConstructor);
-  },
-      _Symbol = function _Symbol2(description) {
-    if (this && this !== G) {
-      throw new TypeError('Symbol is not a constructor');
-    }
-    return setAndGetSymbol(prefix.concat(description || '', random, ++id));
-  },
-      source = create(null),
-      sourceConstructor = { value: _Symbol },
-      sourceMap = function sourceMap(uid) {
-    return source[uid];
-  },
-      $defineProperty = function defineProp(o, key, descriptor) {
-    var uid = '' + key;
-    if (onlySymbols(uid)) {
-      setDescriptor(o, uid, descriptor.enumerable ? copyAsNonEnumerable(descriptor) : descriptor);
-      addInternalIfNeeded(o, uid, !!descriptor.enumerable);
-    } else {
-      defineProperty(o, key, descriptor);
-    }
-    return o;
-  },
-      $getOwnPropertySymbols = function getOwnPropertySymbols(o) {
-    var cof = toString.call(o);
-    o = cof === '[object String]' ? o.split('') : Object(o);
-    return gOPN(o).filter(onlySymbols).map(sourceMap);
-  };
-
-  descriptor.value = $defineProperty;
-  defineProperty(Object, DP, descriptor);
-
-  descriptor.value = $getOwnPropertySymbols;
-  defineProperty(Object, GOPS, descriptor);
-
-  descriptor.value = function getOwnPropertyNames(o) {
-    return gOPN(o).filter(onlyNonSymbols);
-  };
-  defineProperty(Object, GOPN, descriptor);
-
-  descriptor.value = function defineProperties(o, descriptors) {
-    var symbols = $getOwnPropertySymbols(descriptors);
-    if (symbols.length) {
-      keys(descriptors).concat(symbols).forEach(function (uid) {
-        if (propertyIsEnumerable.call(descriptors, uid)) {
-          $defineProperty(o, uid, descriptors[uid]);
+      o[internalSymbol]['@@' + uid] = enumerable;
+    },
+        createWithSymbols = function createWithSymbols(proto, descriptors) {
+      var self = create(proto);
+      gOPN(descriptors).forEach(function (key) {
+        if (propertyIsEnumerable.call(descriptors, key)) {
+          $defineProperty(self, key, descriptors[key]);
         }
       });
-    } else {
-      $defineProperties(o, descriptors);
-    }
-    return o;
-  };
-  defineProperty(Object, DPies, descriptor);
+      return self;
+    },
+        copyAsNonEnumerable = function copyAsNonEnumerable(descriptor) {
+      var newDescriptor = create(descriptor);
+      newDescriptor.enumerable = false;
+      return newDescriptor;
+    },
+        get = function get() {},
+        onlyNonSymbols = function onlyNonSymbols(name) {
+      return name != internalSymbol && !hOP.call(source, name);
+    },
+        onlySymbols = function onlySymbols(name) {
+      return name != internalSymbol && hOP.call(source, name);
+    },
+        propertyIsEnumerable = function propertyIsEnumerable(key) {
+      var uid = '' + key;
+      return onlySymbols(uid) ? hOP.call(this, uid) && this[internalSymbol]['@@' + uid] : pIE.call(this, key);
+    },
+        setAndGetSymbol = function setAndGetSymbol(uid) {
+      var descriptor = {
+        enumerable: false,
+        configurable: true,
+        get: get,
+        set: function set(value) {
+          setDescriptor(this, uid, {
+            enumerable: false,
+            configurable: true,
+            writable: true,
+            value: value
+          });
+          addInternalIfNeeded(this, uid, true);
+        }
+      };
+      defineProperty(ObjectProto, uid, descriptor);
+      return source[uid] = defineProperty(Object(uid), 'constructor', sourceConstructor);
+    },
+        _Symbol = function _Symbol2(description) {
+      if (this && this !== G) {
+        throw new TypeError('Symbol is not a constructor');
+      }
+      return setAndGetSymbol(prefix.concat(description || '', random, ++id));
+    },
+        source = create(null),
+        sourceConstructor = { value: _Symbol },
+        sourceMap = function sourceMap(uid) {
+      return source[uid];
+    },
+        $defineProperty = function defineProp(o, key, descriptor) {
+      var uid = '' + key;
+      if (onlySymbols(uid)) {
+        setDescriptor(o, uid, descriptor.enumerable ? copyAsNonEnumerable(descriptor) : descriptor);
+        addInternalIfNeeded(o, uid, !!descriptor.enumerable);
+      } else {
+        defineProperty(o, key, descriptor);
+      }
+      return o;
+    },
+        $getOwnPropertySymbols = function getOwnPropertySymbols(o) {
+      var cof = toString.call(o);
+      o = cof === '[object String]' ? o.split('') : Object(o);
+      return gOPN(o).filter(onlySymbols).map(sourceMap);
+    };
 
-  descriptor.value = propertyIsEnumerable;
-  defineProperty(ObjectProto, PIE, descriptor);
+    descriptor.value = $defineProperty;
+    defineProperty(Object, DP, descriptor);
 
-  descriptor.value = _Symbol;
-  defineProperty(G, 'Symbol', descriptor);
+    descriptor.value = $getOwnPropertySymbols;
+    defineProperty(Object, GOPS, descriptor);
 
-  descriptor.value = function (key) {
-    var uid = prefix.concat(prefix, key, random);
-    return uid in ObjectProto ? source[uid] : setAndGetSymbol(uid);
-  };
-  defineProperty(_Symbol, 'for', descriptor);
+    descriptor.value = function getOwnPropertyNames(o) {
+      return gOPN(o).filter(onlyNonSymbols);
+    };
+    defineProperty(Object, GOPN, descriptor);
+
+    descriptor.value = function defineProperties(o, descriptors) {
+      var symbols = $getOwnPropertySymbols(descriptors);
+      if (symbols.length) {
+        keys(descriptors).concat(symbols).forEach(function (uid) {
+          if (propertyIsEnumerable.call(descriptors, uid)) {
+            $defineProperty(o, uid, descriptors[uid]);
+          }
+        });
+      } else {
+        $defineProperties(o, descriptors);
+      }
+      return o;
+    };
+    defineProperty(Object, DPies, descriptor);
 
-  descriptor.value = function (symbol) {
-    return hOP.call(source, symbol) ? symbol.slice(prefixLength * 2, -random.length) : void 0;
-  };
-  defineProperty(_Symbol, 'keyFor', descriptor);
+    descriptor.value = propertyIsEnumerable;
+    defineProperty(ObjectProto, PIE, descriptor);
 
-  descriptor.value = function getOwnPropertyDescriptor(o, key) {
-    var descriptor = gOPD(o, key);
-    if (descriptor && onlySymbols(key)) {
-      descriptor.enumerable = propertyIsEnumerable.call(o, key);
-    }
-    return descriptor;
-  };
-  defineProperty(Object, GOPD, descriptor);
+    descriptor.value = _Symbol;
+    defineProperty(G, 'Symbol', descriptor);
 
-  descriptor.value = function (proto, descriptors) {
-    return arguments.length === 1 ? create(proto) : createWithSymbols(proto, descriptors);
-  };
-  defineProperty(Object, 'create', descriptor);
+    descriptor.value = function (key) {
+      var uid = prefix.concat(prefix, key, random);
+      return uid in ObjectProto ? source[uid] : setAndGetSymbol(uid);
+    };
+    defineProperty(_Symbol, 'for', descriptor);
 
-  descriptor.value = function () {
-    var str = toString.call(this);
-    return str === '[object String]' && onlySymbols(this) ? '[object Symbol]' : str;
-  };
-  defineProperty(ObjectProto, 'toString', descriptor);
+    descriptor.value = function (symbol) {
+      return hOP.call(source, symbol) ? symbol.slice(prefixLength * 2, -random.length) : void 0;
+    };
+    defineProperty(_Symbol, 'keyFor', descriptor);
 
-  try {
-    setDescriptor = create(defineProperty({}, prefix, {
-      get: function get() {
-        return defineProperty(this, prefix, { value: false })[prefix];
+    descriptor.value = function getOwnPropertyDescriptor(o, key) {
+      var descriptor = gOPD(o, key);
+      if (descriptor && onlySymbols(key)) {
+        descriptor.enumerable = propertyIsEnumerable.call(o, key);
       }
-    }))[prefix] || defineProperty;
-  } catch (o_O) {
-    setDescriptor = function setDescriptor(o, key, descriptor) {
-      var protoDescriptor = gOPD(ObjectProto, key);
-      delete ObjectProto[key];
-      defineProperty(o, key, descriptor);
-      defineProperty(ObjectProto, key, protoDescriptor);
+      return descriptor;
     };
-  }
-})(Object, 'getOwnPropertySymbols');
-
-(function (O, S) {
-  var dP = O.defineProperty,
-      ObjectProto = O.prototype,
-      toString = ObjectProto.toString,
-      toStringTag = 'toStringTag',
-      descriptor;
-  ['iterator', 'match', 'replace', 'search', 'split', 'hasInstance', 'isConcatSpreadable', 'unscopables', 'species', 'toPrimitive', toStringTag].forEach(function (name) {
-    if (!(name in Symbol)) {
-      dP(Symbol, name, { value: Symbol(name) });
-      switch (name) {
-        case toStringTag:
-          descriptor = O.getOwnPropertyDescriptor(ObjectProto, 'toString');
-          descriptor.value = function () {
-            var str = toString.call(this),
-                tst = typeof this === 'undefined' || this === null ? undefined : this[Symbol.toStringTag];
-            return typeof tst === 'undefined' ? str : '[object ' + tst + ']';
-          };
-          dP(ObjectProto, 'toString', descriptor);
-          break;
-      }
-    }
-  });
-})(Object, Symbol);
+    defineProperty(Object, GOPD, descriptor);
 
-(function (Si, AP, SP) {
+    descriptor.value = function (proto, descriptors) {
+      return arguments.length === 1 ? create(proto) : createWithSymbols(proto, descriptors);
+    };
+    defineProperty(Object, 'create', descriptor);
 
-  function returnThis() {
-    return this;
-  }
+    descriptor.value = function () {
+      var str = toString.call(this);
+      return str === '[object String]' && onlySymbols(this) ? '[object Symbol]' : str;
+    };
+    defineProperty(ObjectProto, 'toString', descriptor);
 
-  if (!AP[Si]) AP[Si] = function () {
-    var i = 0,
-        self = this,
-        iterator = {
-      next: function next() {
-        var done = self.length <= i;
-        return done ? { done: done } : { done: done, value: self[i++] };
+    try {
+      setDescriptor = create(defineProperty({}, prefix, {
+        get: function get() {
+          return defineProperty(this, prefix, { value: false })[prefix];
+        }
+      }))[prefix] || defineProperty;
+    } catch (o_O) {
+      setDescriptor = function setDescriptor(o, key, descriptor) {
+        var protoDescriptor = gOPD(ObjectProto, key);
+        delete ObjectProto[key];
+        defineProperty(o, key, descriptor);
+        defineProperty(ObjectProto, key, protoDescriptor);
+      };
+    }
+  })(Object, 'getOwnPropertySymbols');
+
+  (function (O, S) {
+    var dP = O.defineProperty,
+        ObjectProto = O.prototype,
+        toString = ObjectProto.toString,
+        toStringTag = 'toStringTag',
+        descriptor;
+    ['iterator', 'match', 'replace', 'search', 'split', 'hasInstance', 'isConcatSpreadable', 'unscopables', 'species', 'toPrimitive', toStringTag].forEach(function (name) {
+      if (!(name in Symbol)) {
+        dP(Symbol, name, { value: Symbol(name) });
+        switch (name) {
+          case toStringTag:
+            descriptor = O.getOwnPropertyDescriptor(ObjectProto, 'toString');
+            descriptor.value = function () {
+              var str = toString.call(this),
+                  tst = typeof this === 'undefined' || this === null ? undefined : this[Symbol.toStringTag];
+              return typeof tst === 'undefined' ? str : '[object ' + tst + ']';
+            };
+            dP(ObjectProto, 'toString', descriptor);
+            break;
+        }
       }
+    });
+  })(Object, Symbol);
+
+  (function (Si, AP, SP) {
+
+    function returnThis() {
+      return this;
+    }
+
+    if (!AP[Si]) AP[Si] = function () {
+      var i = 0,
+          self = this,
+          iterator = {
+        next: function next() {
+          var done = self.length <= i;
+          return done ? { done: done } : { done: done, value: self[i++] };
+        }
+      };
+      iterator[Si] = returnThis;
+      return iterator;
     };
-    iterator[Si] = returnThis;
-    return iterator;
-  };
 
-  if (!SP[Si]) SP[Si] = function () {
-    var fromCodePoint = String.fromCodePoint,
-        self = this,
-        i = 0,
-        length = self.length,
-        iterator = {
-      next: function next() {
-        var done = length <= i,
-            c = done ? '' : fromCodePoint(self.codePointAt(i));
-        i += c.length;
-        return done ? { done: done } : { done: done, value: c };
-      }
+    if (!SP[Si]) SP[Si] = function () {
+      var fromCodePoint = String.fromCodePoint,
+          self = this,
+          i = 0,
+          length = self.length,
+          iterator = {
+        next: function next() {
+          var done = length <= i,
+              c = done ? '' : fromCodePoint(self.codePointAt(i));
+          i += c.length;
+          return done ? { done: done } : { done: done, value: c };
+        }
+      };
+      iterator[Si] = returnThis;
+      return iterator;
     };
-    iterator[Si] = returnThis;
-    return iterator;
+  })(Symbol.iterator, Array.prototype, String.prototype);
+}
+
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
+  Number.isNaN = Number.isNaN || function (value) {
+    return value !== value;
   };
-})(Symbol.iterator, Array.prototype, String.prototype);
 
-Number.isNaN = Number.isNaN || function (value) {
-  return value !== value;
-};
+  Number.isFinite = Number.isFinite || function (value) {
+    return typeof value === "number" && isFinite(value);
+  };
+}
 
-Number.isFinite = Number.isFinite || function (value) {
-  return typeof value === "number" && isFinite(value);
-};
 if (!String.prototype.endsWith || function () {
   try {
     return !"ab".endsWith("a", 1);
@@ -295,109 +302,112 @@ if (!String.prototype.startsWith || function () {
   };
 }
 
-if (!Array.from) {
-  Array.from = function () {
-    var toInteger = function toInteger(it) {
-      return isNaN(it = +it) ? 0 : (it > 0 ? Math.floor : Math.ceil)(it);
-    };
-    var toLength = function toLength(it) {
-      return it > 0 ? Math.min(toInteger(it), 0x1fffffffffffff) : 0;
-    };
-    var iterCall = function iterCall(iter, fn, val, index) {
-      try {
-        return fn(val, index);
-      } catch (E) {
-        if (typeof iter.return == 'function') iter.return();
-        throw E;
-      }
-    };
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-    return function from(arrayLike) {
-      var O = Object(arrayLike),
-          C = typeof this == 'function' ? this : Array,
-          aLen = arguments.length,
-          mapfn = aLen > 1 ? arguments[1] : undefined,
-          mapping = mapfn !== undefined,
-          index = 0,
-          iterFn = O[Symbol.iterator],
-          length,
-          result,
-          step,
-          iterator;
-      if (mapping) mapfn = mapfn.bind(aLen > 2 ? arguments[2] : undefined);
-      if (iterFn != undefined && !Array.isArray(arrayLike)) {
-        for (iterator = iterFn.call(O), result = new C(); !(step = iterator.next()).done; index++) {
-          result[index] = mapping ? iterCall(iterator, mapfn, step.value, index) : step.value;
+  if (!Array.from) {
+    Array.from = function () {
+      var toInteger = function toInteger(it) {
+        return isNaN(it = +it) ? 0 : (it > 0 ? Math.floor : Math.ceil)(it);
+      };
+      var toLength = function toLength(it) {
+        return it > 0 ? Math.min(toInteger(it), 0x1fffffffffffff) : 0;
+      };
+      var iterCall = function iterCall(iter, fn, val, index) {
+        try {
+          return fn(val, index);
+        } catch (E) {
+          if (typeof iter.return == 'function') iter.return();
+          throw E;
         }
-      } else {
-        length = toLength(O.length);
-        for (result = new C(length); length > index; index++) {
-          result[index] = mapping ? mapfn(O[index], index) : O[index];
+      };
+
+      return function from(arrayLike) {
+        var O = Object(arrayLike),
+            C = typeof this == 'function' ? this : Array,
+            aLen = arguments.length,
+            mapfn = aLen > 1 ? arguments[1] : undefined,
+            mapping = mapfn !== undefined,
+            index = 0,
+            iterFn = O[Symbol.iterator],
+            length,
+            result,
+            step,
+            iterator;
+        if (mapping) mapfn = mapfn.bind(aLen > 2 ? arguments[2] : undefined);
+        if (iterFn != undefined && !Array.isArray(arrayLike)) {
+          for (iterator = iterFn.call(O), result = new C(); !(step = iterator.next()).done; index++) {
+            result[index] = mapping ? iterCall(iterator, mapfn, step.value, index) : step.value;
+          }
+        } else {
+          length = toLength(O.length);
+          for (result = new C(length); length > index; index++) {
+            result[index] = mapping ? mapfn(O[index], index) : O[index];
+          }
         }
-      }
-      result.length = index;
-      return result;
-    };
-  }();
-}
+        result.length = index;
+        return result;
+      };
+    }();
+  }
 
-if (!Array.prototype.find) {
-  Object.defineProperty(Array.prototype, 'find', {
-    configurable: true,
-    writable: true,
-    enumerable: false,
-    value: function value(predicate) {
-      if (this === null) {
-        throw new TypeError('Array.prototype.find called on null or undefined');
-      }
-      if (typeof predicate !== 'function') {
-        throw new TypeError('predicate must be a function');
-      }
-      var list = Object(this);
-      var length = list.length >>> 0;
-      var thisArg = arguments[1];
-      var value;
-
-      for (var i = 0; i < length; i++) {
-        value = list[i];
-        if (predicate.call(thisArg, value, i, list)) {
-          return value;
+  if (!Array.prototype.find) {
+    Object.defineProperty(Array.prototype, 'find', {
+      configurable: true,
+      writable: true,
+      enumerable: false,
+      value: function value(predicate) {
+        if (this === null) {
+          throw new TypeError('Array.prototype.find called on null or undefined');
         }
+        if (typeof predicate !== 'function') {
+          throw new TypeError('predicate must be a function');
+        }
+        var list = Object(this);
+        var length = list.length >>> 0;
+        var thisArg = arguments[1];
+        var value;
+
+        for (var i = 0; i < length; i++) {
+          value = list[i];
+          if (predicate.call(thisArg, value, i, list)) {
+            return value;
+          }
+        }
+        return undefined;
       }
-      return undefined;
-    }
-  });
-}
+    });
+  }
 
-if (!Array.prototype.findIndex) {
-  Object.defineProperty(Array.prototype, 'findIndex', {
-    configurable: true,
-    writable: true,
-    enumerable: false,
-    value: function value(predicate) {
-      if (this === null) {
-        throw new TypeError('Array.prototype.findIndex called on null or undefined');
-      }
-      if (typeof predicate !== 'function') {
-        throw new TypeError('predicate must be a function');
-      }
-      var list = Object(this);
-      var length = list.length >>> 0;
-      var thisArg = arguments[1];
-      var value;
-
-      for (var i = 0; i < length; i++) {
-        value = list[i];
-        if (predicate.call(thisArg, value, i, list)) {
-          return i;
+  if (!Array.prototype.findIndex) {
+    Object.defineProperty(Array.prototype, 'findIndex', {
+      configurable: true,
+      writable: true,
+      enumerable: false,
+      value: function value(predicate) {
+        if (this === null) {
+          throw new TypeError('Array.prototype.findIndex called on null or undefined');
         }
+        if (typeof predicate !== 'function') {
+          throw new TypeError('predicate must be a function');
+        }
+        var list = Object(this);
+        var length = list.length >>> 0;
+        var thisArg = arguments[1];
+        var value;
+
+        for (var i = 0; i < length; i++) {
+          value = list[i];
+          if (predicate.call(thisArg, value, i, list)) {
+            return i;
+          }
+        }
+        return -1;
       }
-      return -1;
-    }
-  });
+    });
+  }
 }
 
-if (!Array.prototype.includes) {
+if (typeof FEATURE_NO_ES2016 === 'undefined' && !Array.prototype.includes) {
   Object.defineProperty(Array.prototype, 'includes', {
     configurable: true,
     writable: true,
@@ -431,375 +441,392 @@ if (!Array.prototype.includes) {
   });
 }
 
-(function () {
-  var needsFix = false;
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-  try {
-    var s = Object.keys('a');
-    needsFix = s.length !== 1 || s[0] !== '0';
-  } catch (e) {
-    needsFix = true;
-  }
+  (function () {
+    var needsFix = false;
 
-  if (needsFix) {
-    Object.keys = function () {
-      var hasOwnProperty = Object.prototype.hasOwnProperty,
-          hasDontEnumBug = !{ toString: null }.propertyIsEnumerable('toString'),
-          dontEnums = ['toString', 'toLocaleString', 'valueOf', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable', 'constructor'],
-          dontEnumsLength = dontEnums.length;
+    try {
+      var s = Object.keys('a');
+      needsFix = s.length !== 1 || s[0] !== '0';
+    } catch (e) {
+      needsFix = true;
+    }
 
-      return function (obj) {
-        if (obj === undefined || obj === null) {
-          throw TypeError('Cannot convert undefined or null to object');
-        }
+    if (needsFix) {
+      Object.keys = function () {
+        var hasOwnProperty = Object.prototype.hasOwnProperty,
+            hasDontEnumBug = !{ toString: null }.propertyIsEnumerable('toString'),
+            dontEnums = ['toString', 'toLocaleString', 'valueOf', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable', 'constructor'],
+            dontEnumsLength = dontEnums.length;
+
+        return function (obj) {
+          if (obj === undefined || obj === null) {
+            throw TypeError('Cannot convert undefined or null to object');
+          }
 
-        obj = Object(obj);
+          obj = Object(obj);
 
-        var result = [],
-            prop,
-            i;
+          var result = [],
+              prop,
+              i;
 
-        for (prop in obj) {
-          if (hasOwnProperty.call(obj, prop)) {
-            result.push(prop);
+          for (prop in obj) {
+            if (hasOwnProperty.call(obj, prop)) {
+              result.push(prop);
+            }
           }
-        }
 
-        if (hasDontEnumBug) {
-          for (i = 0; i < dontEnumsLength; i++) {
-            if (hasOwnProperty.call(obj, dontEnums[i])) {
-              result.push(dontEnums[i]);
+          if (hasDontEnumBug) {
+            for (i = 0; i < dontEnumsLength; i++) {
+              if (hasOwnProperty.call(obj, dontEnums[i])) {
+                result.push(dontEnums[i]);
+              }
             }
           }
-        }
 
-        return result;
-      };
-    }();
-  }
-})();
+          return result;
+        };
+      }();
+    }
+  })();
 
-(function (O) {
-  if ('assign' in O) {
-    return;
-  }
+  (function (O) {
+    if ('assign' in O) {
+      return;
+    }
 
-  O.defineProperty(O, 'assign', {
-    configurable: true,
-    writable: true,
-    value: function () {
-      var gOPS = O.getOwnPropertySymbols,
-          pIE = O.propertyIsEnumerable,
-          filterOS = gOPS ? function (self) {
-        return gOPS(self).filter(pIE, self);
-      } : function () {
-        return Array.prototype;
-      };
+    O.defineProperty(O, 'assign', {
+      configurable: true,
+      writable: true,
+      value: function () {
+        var gOPS = O.getOwnPropertySymbols,
+            pIE = O.propertyIsEnumerable,
+            filterOS = gOPS ? function (self) {
+          return gOPS(self).filter(pIE, self);
+        } : function () {
+          return Array.prototype;
+        };
+
+        return function assign(where) {
+          if (gOPS && !(where instanceof O)) {
+            console.warn('problematic Symbols', where);
+          }
 
-      return function assign(where) {
-        if (gOPS && !(where instanceof O)) {
-          console.warn('problematic Symbols', where);
-        }
+          function set(keyOrSymbol) {
+            where[keyOrSymbol] = arg[keyOrSymbol];
+          }
 
-        function set(keyOrSymbol) {
-          where[keyOrSymbol] = arg[keyOrSymbol];
-        }
+          for (var i = 1, ii = arguments.length; i < ii; ++i) {
+            var arg = arguments[i];
 
-        for (var i = 1, ii = arguments.length; i < ii; ++i) {
-          var arg = arguments[i];
+            if (arg === null || arg === undefined) {
+              continue;
+            }
 
-          if (arg === null || arg === undefined) {
-            continue;
+            O.keys(arg).concat(filterOS(arg)).forEach(set);
           }
 
-          O.keys(arg).concat(filterOS(arg)).forEach(set);
-        }
-
-        return where;
-      };
-    }()
-  });
-})(Object);
-
-(function (global) {
-  var i;
+          return where;
+        };
+      }()
+    });
+  })(Object);
+}
 
-  var defineProperty = Object.defineProperty,
-      is = function is(a, b) {
-    return a === b || a !== a && b !== b;
-  };
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-  if (typeof WeakMap == 'undefined') {
-    global.WeakMap = createCollection({
-      'delete': sharedDelete,
+  (function (global) {
+    var i;
 
-      clear: sharedClear,
+    var defineProperty = Object.defineProperty,
+        is = function is(a, b) {
+      return a === b || a !== a && b !== b;
+    };
 
-      get: sharedGet,
+    if (typeof WeakMap == 'undefined') {
+      global.WeakMap = createCollection({
+        'delete': sharedDelete,
 
-      has: mapHas,
+        clear: sharedClear,
 
-      set: sharedSet
-    }, true);
-  }
+        get: sharedGet,
 
-  if (typeof Map == 'undefined' || typeof new Map().values !== 'function' || !new Map().values().next) {
-    var _createCollection;
+        has: mapHas,
 
-    global.Map = createCollection((_createCollection = {
-      'delete': sharedDelete,
+        set: sharedSet
+      }, true);
+    }
 
-      has: mapHas,
+    if (typeof Map == 'undefined' || typeof new Map().values !== 'function' || !new Map().values().next) {
+      var _createCollection;
 
-      get: sharedGet,
+      global.Map = createCollection((_createCollection = {
+        'delete': sharedDelete,
 
-      set: sharedSet,
+        has: mapHas,
 
-      keys: sharedKeys,
+        get: sharedGet,
 
-      values: sharedValues,
+        set: sharedSet,
 
-      entries: mapEntries,
+        keys: sharedKeys,
 
-      forEach: sharedForEach,
+        values: sharedValues,
 
-      clear: sharedClear
-    }, _createCollection[Symbol.iterator] = mapEntries, _createCollection));
-  }
+        entries: mapEntries,
 
-  if (typeof Set == 'undefined' || typeof new Set().values !== 'function' || !new Set().values().next) {
-    var _createCollection2;
+        forEach: sharedForEach,
 
-    global.Set = createCollection((_createCollection2 = {
-      has: setHas,
+        clear: sharedClear
+      }, _createCollection[Symbol.iterator] = mapEntries, _createCollection));
+    }
 
-      add: sharedAdd,
+    if (typeof Set == 'undefined' || typeof new Set().values !== 'function' || !new Set().values().next) {
+      var _createCollection2;
 
-      'delete': sharedDelete,
+      global.Set = createCollection((_createCollection2 = {
+        has: setHas,
 
-      clear: sharedClear,
+        add: sharedAdd,
 
-      keys: sharedValues,
-      values: sharedValues,
+        'delete': sharedDelete,
 
-      entries: setEntries,
+        clear: sharedClear,
 
-      forEach: sharedForEach
-    }, _createCollection2[Symbol.iterator] = sharedValues, _createCollection2));
-  }
+        keys: sharedValues,
+        values: sharedValues,
 
-  if (typeof WeakSet == 'undefined') {
-    global.WeakSet = createCollection({
-      'delete': sharedDelete,
+        entries: setEntries,
 
-      add: sharedAdd,
+        forEach: sharedForEach
+      }, _createCollection2[Symbol.iterator] = sharedValues, _createCollection2));
+    }
 
-      clear: sharedClear,
+    if (typeof WeakSet == 'undefined') {
+      global.WeakSet = createCollection({
+        'delete': sharedDelete,
 
-      has: setHas
-    }, true);
-  }
+        add: sharedAdd,
 
-  function createCollection(proto, objectOnly) {
-    function Collection(a) {
-      if (!this || this.constructor !== Collection) return new Collection(a);
-      this._keys = [];
-      this._values = [];
-      this._itp = [];
-      this.objectOnly = objectOnly;
+        clear: sharedClear,
 
-      if (a) init.call(this, a);
+        has: setHas
+      }, true);
     }
 
-    if (!objectOnly) {
-      defineProperty(proto, 'size', {
-        get: sharedSize
-      });
-    }
+    function createCollection(proto, objectOnly) {
+      function Collection(a) {
+        if (!this || this.constructor !== Collection) return new Collection(a);
+        this._keys = [];
+        this._values = [];
+        this._itp = [];
+        this.objectOnly = objectOnly;
 
-    proto.constructor = Collection;
-    Collection.prototype = proto;
+        if (a) init.call(this, a);
+      }
 
-    return Collection;
-  }
+      if (!objectOnly) {
+        defineProperty(proto, 'size', {
+          get: sharedSize
+        });
+      }
 
-  function init(a) {
-    var i;
+      proto.constructor = Collection;
+      Collection.prototype = proto;
 
-    if (this.add) a.forEach(this.add, this);else a.forEach(function (a) {
-        this.set(a[0], a[1]);
-      }, this);
-  }
+      return Collection;
+    }
 
-  function sharedDelete(key) {
-    if (this.has(key)) {
-      this._keys.splice(i, 1);
-      this._values.splice(i, 1);
+    function init(a) {
+      var i;
 
-      this._itp.forEach(function (p) {
-        if (i < p[0]) p[0]--;
-      });
+      if (this.add) a.forEach(this.add, this);else a.forEach(function (a) {
+          this.set(a[0], a[1]);
+        }, this);
     }
 
-    return -1 < i;
-  };
-
-  function sharedGet(key) {
-    return this.has(key) ? this._values[i] : undefined;
-  }
+    function sharedDelete(key) {
+      if (this.has(key)) {
+        this._keys.splice(i, 1);
+        this._values.splice(i, 1);
 
-  function has(list, key) {
-    if (this.objectOnly && key !== Object(key)) throw new TypeError("Invalid value used as weak collection key");
+        this._itp.forEach(function (p) {
+          if (i < p[0]) p[0]--;
+        });
+      }
 
-    if (key != key || key === 0) for (i = list.length; i-- && !is(list[i], key);) {} else i = list.indexOf(key);
-    return -1 < i;
-  }
+      return -1 < i;
+    };
 
-  function setHas(value) {
-    return has.call(this, this._values, value);
-  }
+    function sharedGet(key) {
+      return this.has(key) ? this._values[i] : undefined;
+    }
 
-  function mapHas(value) {
-    return has.call(this, this._keys, value);
-  }
+    function has(list, key) {
+      if (this.objectOnly && key !== Object(key)) throw new TypeError("Invalid value used as weak collection key");
 
-  function sharedSet(key, value) {
-    this.has(key) ? this._values[i] = value : this._values[this._keys.push(key) - 1] = value;
-    return this;
-  }
+      if (key != key || key === 0) for (i = list.length; i-- && !is(list[i], key);) {} else i = list.indexOf(key);
+      return -1 < i;
+    }
 
-  function sharedAdd(value) {
-    if (!this.has(value)) this._values.push(value);
-    return this;
-  }
+    function setHas(value) {
+      return has.call(this, this._values, value);
+    }
 
-  function sharedClear() {
-    (this._keys || 0).length = this._values.length = 0;
-  }
+    function mapHas(value) {
+      return has.call(this, this._keys, value);
+    }
 
-  function sharedKeys() {
-    return sharedIterator(this._itp, this._keys);
-  }
+    function sharedSet(key, value) {
+      this.has(key) ? this._values[i] = value : this._values[this._keys.push(key) - 1] = value;
+      return this;
+    }
 
-  function sharedValues() {
-    return sharedIterator(this._itp, this._values);
-  }
+    function sharedAdd(value) {
+      if (!this.has(value)) this._values.push(value);
+      return this;
+    }
 
-  function mapEntries() {
-    return sharedIterator(this._itp, this._keys, this._values);
-  }
+    function sharedClear() {
+      (this._keys || 0).length = this._values.length = 0;
+    }
 
-  function setEntries() {
-    return sharedIterator(this._itp, this._values, this._values);
-  }
+    function sharedKeys() {
+      return sharedIterator(this._itp, this._keys);
+    }
 
-  function sharedIterator(itp, array, array2) {
-    var _ref;
+    function sharedValues() {
+      return sharedIterator(this._itp, this._values);
+    }
 
-    var p = [0],
-        done = false;
-    itp.push(p);
-    return _ref = {}, _ref[Symbol.iterator] = function () {
-      return this;
-    }, _ref.next = function next() {
-      var v,
-          k = p[0];
-      if (!done && k < array.length) {
-        v = array2 ? [array[k], array2[k]] : array[k];
-        p[0]++;
-      } else {
-        done = true;
-        itp.splice(itp.indexOf(p), 1);
-      }
-      return { done: done, value: v };
-    }, _ref;
-  }
+    function mapEntries() {
+      return sharedIterator(this._itp, this._keys, this._values);
+    }
 
-  function sharedSize() {
-    return this._values.length;
-  }
+    function setEntries() {
+      return sharedIterator(this._itp, this._values, this._values);
+    }
 
-  function sharedForEach(callback, context) {
-    var it = this.entries();
-    for (;;) {
-      var r = it.next();
-      if (r.done) break;
-      callback.call(context, r.value[1], r.value[0], this);
+    function sharedIterator(itp, array, array2) {
+      var _ref;
+
+      var p = [0],
+          done = false;
+      itp.push(p);
+      return _ref = {}, _ref[Symbol.iterator] = function () {
+        return this;
+      }, _ref.next = function next() {
+        var v,
+            k = p[0];
+        if (!done && k < array.length) {
+          v = array2 ? [array[k], array2[k]] : array[k];
+          p[0]++;
+        } else {
+          done = true;
+          itp.splice(itp.indexOf(p), 1);
+        }
+        return { done: done, value: v };
+      }, _ref;
     }
-  }
-})(_aureliaPal.PLATFORM.global);
 
-var emptyMetadata = Object.freeze({});
-var metadataContainerKey = '__metadata__';
-var bind = Function.prototype.bind;
+    function sharedSize() {
+      return this._values.length;
+    }
 
-if (typeof _aureliaPal.PLATFORM.global.Reflect === 'undefined') {
-  _aureliaPal.PLATFORM.global.Reflect = {};
+    function sharedForEach(callback, context) {
+      var it = this.entries();
+      for (;;) {
+        var r = it.next();
+        if (r.done) break;
+        callback.call(context, r.value[1], r.value[0], this);
+      }
+    }
+  })(_aureliaPal.PLATFORM.global);
 }
 
-if (typeof Reflect.getOwnMetadata !== 'function') {
-  Reflect.getOwnMetadata = function (metadataKey, target, targetKey) {
-    if (target.hasOwnProperty(metadataContainerKey)) {
-      return (target[metadataContainerKey][targetKey] || emptyMetadata)[metadataKey];
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+  (function () {
+
+    var bind = Function.prototype.bind;
+
+    if (typeof _aureliaPal.PLATFORM.global.Reflect === 'undefined') {
+      _aureliaPal.PLATFORM.global.Reflect = {};
     }
-  };
-}
 
-if (typeof Reflect.defineMetadata !== 'function') {
-  Reflect.defineMetadata = function (metadataKey, metadataValue, target, targetKey) {
-    var metadataContainer = target.hasOwnProperty(metadataContainerKey) ? target[metadataContainerKey] : target[metadataContainerKey] = {};
-    var targetContainer = metadataContainer[targetKey] || (metadataContainer[targetKey] = {});
-    targetContainer[metadataKey] = metadataValue;
-  };
-}
+    if (typeof Reflect.defineProperty !== 'function') {
+      Reflect.defineProperty = function (target, propertyKey, descriptor) {
+        if ((typeof target === 'undefined' ? 'undefined' : _typeof(target)) === 'object' ? target === null : typeof target !== 'function') {
+          throw new TypeError('Reflect.defineProperty called on non-object');
+        }
+        try {
+          Object.defineProperty(target, propertyKey, descriptor);
+          return true;
+        } catch (e) {
+          return false;
+        }
+      };
+    }
 
-if (typeof Reflect.metadata !== 'function') {
-  Reflect.metadata = function (metadataKey, metadataValue) {
-    return function (target, targetKey) {
-      Reflect.defineMetadata(metadataKey, metadataValue, target, targetKey);
-    };
-  };
-}
+    if (typeof Reflect.construct !== 'function') {
+      Reflect.construct = function (Target, args) {
+        if (args) {
+          switch (args.length) {
+            case 0:
+              return new Target();
+            case 1:
+              return new Target(args[0]);
+            case 2:
+              return new Target(args[0], args[1]);
+            case 3:
+              return new Target(args[0], args[1], args[2]);
+            case 4:
+              return new Target(args[0], args[1], args[2], args[3]);
+          }
+        }
 
-if (typeof Reflect.defineProperty !== 'function') {
-  Reflect.defineProperty = function (target, propertyKey, descriptor) {
-    if ((typeof target === 'undefined' ? 'undefined' : _typeof(target)) === 'object' ? target === null : typeof target !== 'function') {
-      throw new TypeError('Reflect.defineProperty called on non-object');
+        var a = [null];
+        a.push.apply(a, args);
+        return new (bind.apply(Target, a))();
+      };
     }
-    try {
-      Object.defineProperty(target, propertyKey, descriptor);
-      return true;
-    } catch (e) {
-      return false;
+
+    if (typeof Reflect.ownKeys !== 'function') {
+      Reflect.ownKeys = function (o) {
+        return Object.getOwnPropertyNames(o).concat(Object.getOwnPropertySymbols(o));
+      };
     }
-  };
+  })();
 }
 
-if (typeof Reflect.construct !== 'function') {
-  Reflect.construct = function (Target, args) {
-    if (args) {
-      switch (args.length) {
-        case 0:
-          return new Target();
-        case 1:
-          return new Target(args[0]);
-        case 2:
-          return new Target(args[0], args[1]);
-        case 3:
-          return new Target(args[0], args[1], args[2]);
-        case 4:
-          return new Target(args[0], args[1], args[2], args[3]);
-      }
+if (typeof FEATURE_NO_ESNEXT === 'undefined') {
+  (function () {
+
+    var emptyMetadata = Object.freeze({});
+    var metadataContainerKey = '__metadata__';
+
+    if (typeof Reflect.getOwnMetadata !== 'function') {
+      Reflect.getOwnMetadata = function (metadataKey, target, targetKey) {
+        if (target.hasOwnProperty(metadataContainerKey)) {
+          return (target[metadataContainerKey][targetKey] || emptyMetadata)[metadataKey];
+        }
+      };
     }
 
-    var a = [null];
-    a.push.apply(a, args);
-    return new (bind.apply(Target, a))();
-  };
-}
+    if (typeof Reflect.defineMetadata !== 'function') {
+      Reflect.defineMetadata = function (metadataKey, metadataValue, target, targetKey) {
+        var metadataContainer = target.hasOwnProperty(metadataContainerKey) ? target[metadataContainerKey] : target[metadataContainerKey] = {};
+        var targetContainer = metadataContainer[targetKey] || (metadataContainer[targetKey] = {});
+        targetContainer[metadataKey] = metadataValue;
+      };
+    }
 
-if (typeof Reflect.ownKeys !== 'function') {
-  Reflect.ownKeys = function (o) {
-    return Object.getOwnPropertyNames(o).concat(Object.getOwnPropertySymbols(o));
-  };
+    if (typeof Reflect.metadata !== 'function') {
+      Reflect.metadata = function (metadataKey, metadataValue) {
+        return function (target, targetKey) {
+          Reflect.defineMetadata(metadataKey, metadataValue, target, targetKey);
+        };
+      };
+    }
+  })();
 }
\ No newline at end of file
diff --git a/dist/es2015/aurelia-polyfills.js b/dist/es2015/aurelia-polyfills.js
index 828bd44..d2d8e66 100644
--- a/dist/es2015/aurelia-polyfills.js
+++ b/dist/es2015/aurelia-polyfills.js
@@ -1,265 +1,272 @@
 import { PLATFORM } from 'aurelia-pal';
 
-(function (Object, GOPS) {
-  'use strict';
-
-  if (GOPS in Object) return;
-
-  var setDescriptor,
-      G = PLATFORM.global,
-      id = 0,
-      random = '' + Math.random(),
-      prefix = '__\x01symbol:',
-      prefixLength = prefix.length,
-      internalSymbol = '__\x01symbol@@' + random,
-      DP = 'defineProperty',
-      DPies = 'defineProperties',
-      GOPN = 'getOwnPropertyNames',
-      GOPD = 'getOwnPropertyDescriptor',
-      PIE = 'propertyIsEnumerable',
-      gOPN = Object[GOPN],
-      gOPD = Object[GOPD],
-      create = Object.create,
-      keys = Object.keys,
-      defineProperty = Object[DP],
-      $defineProperties = Object[DPies],
-      descriptor = gOPD(Object, GOPN),
-      ObjectProto = Object.prototype,
-      hOP = ObjectProto.hasOwnProperty,
-      pIE = ObjectProto[PIE],
-      toString = ObjectProto.toString,
-      indexOf = Array.prototype.indexOf || function (v) {
-    for (var i = this.length; i-- && this[i] !== v;) {}
-    return i;
-  },
-      addInternalIfNeeded = function (o, uid, enumerable) {
-    if (!hOP.call(o, internalSymbol)) {
-      defineProperty(o, internalSymbol, {
-        enumerable: false,
-        configurable: false,
-        writable: false,
-        value: {}
-      });
-    }
-    o[internalSymbol]['@@' + uid] = enumerable;
-  },
-      createWithSymbols = function (proto, descriptors) {
-    var self = create(proto);
-    gOPN(descriptors).forEach(function (key) {
-      if (propertyIsEnumerable.call(descriptors, key)) {
-        $defineProperty(self, key, descriptors[key]);
-      }
-    });
-    return self;
-  },
-      copyAsNonEnumerable = function (descriptor) {
-    var newDescriptor = create(descriptor);
-    newDescriptor.enumerable = false;
-    return newDescriptor;
-  },
-      get = function get() {},
-      onlyNonSymbols = function (name) {
-    return name != internalSymbol && !hOP.call(source, name);
-  },
-      onlySymbols = function (name) {
-    return name != internalSymbol && hOP.call(source, name);
-  },
-      propertyIsEnumerable = function propertyIsEnumerable(key) {
-    var uid = '' + key;
-    return onlySymbols(uid) ? hOP.call(this, uid) && this[internalSymbol]['@@' + uid] : pIE.call(this, key);
-  },
-      setAndGetSymbol = function (uid) {
-    var descriptor = {
-      enumerable: false,
-      configurable: true,
-      get: get,
-      set: function (value) {
-        setDescriptor(this, uid, {
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
+  (function (Object, GOPS) {
+    'use strict';
+
+    if (GOPS in Object) return;
+
+    var setDescriptor,
+        G = PLATFORM.global,
+        id = 0,
+        random = '' + Math.random(),
+        prefix = '__\x01symbol:',
+        prefixLength = prefix.length,
+        internalSymbol = '__\x01symbol@@' + random,
+        DP = 'defineProperty',
+        DPies = 'defineProperties',
+        GOPN = 'getOwnPropertyNames',
+        GOPD = 'getOwnPropertyDescriptor',
+        PIE = 'propertyIsEnumerable',
+        gOPN = Object[GOPN],
+        gOPD = Object[GOPD],
+        create = Object.create,
+        keys = Object.keys,
+        defineProperty = Object[DP],
+        $defineProperties = Object[DPies],
+        descriptor = gOPD(Object, GOPN),
+        ObjectProto = Object.prototype,
+        hOP = ObjectProto.hasOwnProperty,
+        pIE = ObjectProto[PIE],
+        toString = ObjectProto.toString,
+        indexOf = Array.prototype.indexOf || function (v) {
+      for (var i = this.length; i-- && this[i] !== v;) {}
+      return i;
+    },
+        addInternalIfNeeded = function (o, uid, enumerable) {
+      if (!hOP.call(o, internalSymbol)) {
+        defineProperty(o, internalSymbol, {
           enumerable: false,
-          configurable: true,
-          writable: true,
-          value: value
+          configurable: false,
+          writable: false,
+          value: {}
         });
-        addInternalIfNeeded(this, uid, true);
       }
-    };
-    defineProperty(ObjectProto, uid, descriptor);
-    return source[uid] = defineProperty(Object(uid), 'constructor', sourceConstructor);
-  },
-      Symbol = function Symbol(description) {
-    if (this && this !== G) {
-      throw new TypeError('Symbol is not a constructor');
-    }
-    return setAndGetSymbol(prefix.concat(description || '', random, ++id));
-  },
-      source = create(null),
-      sourceConstructor = { value: Symbol },
-      sourceMap = function (uid) {
-    return source[uid];
-  },
-      $defineProperty = function defineProp(o, key, descriptor) {
-    var uid = '' + key;
-    if (onlySymbols(uid)) {
-      setDescriptor(o, uid, descriptor.enumerable ? copyAsNonEnumerable(descriptor) : descriptor);
-      addInternalIfNeeded(o, uid, !!descriptor.enumerable);
-    } else {
-      defineProperty(o, key, descriptor);
-    }
-    return o;
-  },
-      $getOwnPropertySymbols = function getOwnPropertySymbols(o) {
-    var cof = toString.call(o);
-    o = cof === '[object String]' ? o.split('') : Object(o);
-    return gOPN(o).filter(onlySymbols).map(sourceMap);
-  };
-
-  descriptor.value = $defineProperty;
-  defineProperty(Object, DP, descriptor);
-
-  descriptor.value = $getOwnPropertySymbols;
-  defineProperty(Object, GOPS, descriptor);
-
-  descriptor.value = function getOwnPropertyNames(o) {
-    return gOPN(o).filter(onlyNonSymbols);
-  };
-  defineProperty(Object, GOPN, descriptor);
-
-  descriptor.value = function defineProperties(o, descriptors) {
-    var symbols = $getOwnPropertySymbols(descriptors);
-    if (symbols.length) {
-      keys(descriptors).concat(symbols).forEach(function (uid) {
-        if (propertyIsEnumerable.call(descriptors, uid)) {
-          $defineProperty(o, uid, descriptors[uid]);
+      o[internalSymbol]['@@' + uid] = enumerable;
+    },
+        createWithSymbols = function (proto, descriptors) {
+      var self = create(proto);
+      gOPN(descriptors).forEach(function (key) {
+        if (propertyIsEnumerable.call(descriptors, key)) {
+          $defineProperty(self, key, descriptors[key]);
         }
       });
-    } else {
-      $defineProperties(o, descriptors);
-    }
-    return o;
-  };
-  defineProperty(Object, DPies, descriptor);
+      return self;
+    },
+        copyAsNonEnumerable = function (descriptor) {
+      var newDescriptor = create(descriptor);
+      newDescriptor.enumerable = false;
+      return newDescriptor;
+    },
+        get = function get() {},
+        onlyNonSymbols = function (name) {
+      return name != internalSymbol && !hOP.call(source, name);
+    },
+        onlySymbols = function (name) {
+      return name != internalSymbol && hOP.call(source, name);
+    },
+        propertyIsEnumerable = function propertyIsEnumerable(key) {
+      var uid = '' + key;
+      return onlySymbols(uid) ? hOP.call(this, uid) && this[internalSymbol]['@@' + uid] : pIE.call(this, key);
+    },
+        setAndGetSymbol = function (uid) {
+      var descriptor = {
+        enumerable: false,
+        configurable: true,
+        get: get,
+        set: function (value) {
+          setDescriptor(this, uid, {
+            enumerable: false,
+            configurable: true,
+            writable: true,
+            value: value
+          });
+          addInternalIfNeeded(this, uid, true);
+        }
+      };
+      defineProperty(ObjectProto, uid, descriptor);
+      return source[uid] = defineProperty(Object(uid), 'constructor', sourceConstructor);
+    },
+        Symbol = function Symbol(description) {
+      if (this && this !== G) {
+        throw new TypeError('Symbol is not a constructor');
+      }
+      return setAndGetSymbol(prefix.concat(description || '', random, ++id));
+    },
+        source = create(null),
+        sourceConstructor = { value: Symbol },
+        sourceMap = function (uid) {
+      return source[uid];
+    },
+        $defineProperty = function defineProp(o, key, descriptor) {
+      var uid = '' + key;
+      if (onlySymbols(uid)) {
+        setDescriptor(o, uid, descriptor.enumerable ? copyAsNonEnumerable(descriptor) : descriptor);
+        addInternalIfNeeded(o, uid, !!descriptor.enumerable);
+      } else {
+        defineProperty(o, key, descriptor);
+      }
+      return o;
+    },
+        $getOwnPropertySymbols = function getOwnPropertySymbols(o) {
+      var cof = toString.call(o);
+      o = cof === '[object String]' ? o.split('') : Object(o);
+      return gOPN(o).filter(onlySymbols).map(sourceMap);
+    };
 
-  descriptor.value = propertyIsEnumerable;
-  defineProperty(ObjectProto, PIE, descriptor);
+    descriptor.value = $defineProperty;
+    defineProperty(Object, DP, descriptor);
 
-  descriptor.value = Symbol;
-  defineProperty(G, 'Symbol', descriptor);
+    descriptor.value = $getOwnPropertySymbols;
+    defineProperty(Object, GOPS, descriptor);
 
-  descriptor.value = function (key) {
-    var uid = prefix.concat(prefix, key, random);
-    return uid in ObjectProto ? source[uid] : setAndGetSymbol(uid);
-  };
-  defineProperty(Symbol, 'for', descriptor);
+    descriptor.value = function getOwnPropertyNames(o) {
+      return gOPN(o).filter(onlyNonSymbols);
+    };
+    defineProperty(Object, GOPN, descriptor);
+
+    descriptor.value = function defineProperties(o, descriptors) {
+      var symbols = $getOwnPropertySymbols(descriptors);
+      if (symbols.length) {
+        keys(descriptors).concat(symbols).forEach(function (uid) {
+          if (propertyIsEnumerable.call(descriptors, uid)) {
+            $defineProperty(o, uid, descriptors[uid]);
+          }
+        });
+      } else {
+        $defineProperties(o, descriptors);
+      }
+      return o;
+    };
+    defineProperty(Object, DPies, descriptor);
 
-  descriptor.value = function (symbol) {
-    return hOP.call(source, symbol) ? symbol.slice(prefixLength * 2, -random.length) : void 0;
-  };
-  defineProperty(Symbol, 'keyFor', descriptor);
+    descriptor.value = propertyIsEnumerable;
+    defineProperty(ObjectProto, PIE, descriptor);
 
-  descriptor.value = function getOwnPropertyDescriptor(o, key) {
-    var descriptor = gOPD(o, key);
-    if (descriptor && onlySymbols(key)) {
-      descriptor.enumerable = propertyIsEnumerable.call(o, key);
-    }
-    return descriptor;
-  };
-  defineProperty(Object, GOPD, descriptor);
+    descriptor.value = Symbol;
+    defineProperty(G, 'Symbol', descriptor);
 
-  descriptor.value = function (proto, descriptors) {
-    return arguments.length === 1 ? create(proto) : createWithSymbols(proto, descriptors);
-  };
-  defineProperty(Object, 'create', descriptor);
+    descriptor.value = function (key) {
+      var uid = prefix.concat(prefix, key, random);
+      return uid in ObjectProto ? source[uid] : setAndGetSymbol(uid);
+    };
+    defineProperty(Symbol, 'for', descriptor);
 
-  descriptor.value = function () {
-    var str = toString.call(this);
-    return str === '[object String]' && onlySymbols(this) ? '[object Symbol]' : str;
-  };
-  defineProperty(ObjectProto, 'toString', descriptor);
+    descriptor.value = function (symbol) {
+      return hOP.call(source, symbol) ? symbol.slice(prefixLength * 2, -random.length) : void 0;
+    };
+    defineProperty(Symbol, 'keyFor', descriptor);
 
-  try {
-    setDescriptor = create(defineProperty({}, prefix, {
-      get: function () {
-        return defineProperty(this, prefix, { value: false })[prefix];
+    descriptor.value = function getOwnPropertyDescriptor(o, key) {
+      var descriptor = gOPD(o, key);
+      if (descriptor && onlySymbols(key)) {
+        descriptor.enumerable = propertyIsEnumerable.call(o, key);
       }
-    }))[prefix] || defineProperty;
-  } catch (o_O) {
-    setDescriptor = function (o, key, descriptor) {
-      var protoDescriptor = gOPD(ObjectProto, key);
-      delete ObjectProto[key];
-      defineProperty(o, key, descriptor);
-      defineProperty(ObjectProto, key, protoDescriptor);
+      return descriptor;
     };
-  }
-})(Object, 'getOwnPropertySymbols');
-
-(function (O, S) {
-  var dP = O.defineProperty,
-      ObjectProto = O.prototype,
-      toString = ObjectProto.toString,
-      toStringTag = 'toStringTag',
-      descriptor;
-  ['iterator', 'match', 'replace', 'search', 'split', 'hasInstance', 'isConcatSpreadable', 'unscopables', 'species', 'toPrimitive', toStringTag].forEach(function (name) {
-    if (!(name in Symbol)) {
-      dP(Symbol, name, { value: Symbol(name) });
-      switch (name) {
-        case toStringTag:
-          descriptor = O.getOwnPropertyDescriptor(ObjectProto, 'toString');
-          descriptor.value = function () {
-            var str = toString.call(this),
-                tst = typeof this === 'undefined' || this === null ? undefined : this[Symbol.toStringTag];
-            return typeof tst === 'undefined' ? str : '[object ' + tst + ']';
-          };
-          dP(ObjectProto, 'toString', descriptor);
-          break;
-      }
-    }
-  });
-})(Object, Symbol);
+    defineProperty(Object, GOPD, descriptor);
 
-(function (Si, AP, SP) {
+    descriptor.value = function (proto, descriptors) {
+      return arguments.length === 1 ? create(proto) : createWithSymbols(proto, descriptors);
+    };
+    defineProperty(Object, 'create', descriptor);
 
-  function returnThis() {
-    return this;
-  }
+    descriptor.value = function () {
+      var str = toString.call(this);
+      return str === '[object String]' && onlySymbols(this) ? '[object Symbol]' : str;
+    };
+    defineProperty(ObjectProto, 'toString', descriptor);
 
-  if (!AP[Si]) AP[Si] = function () {
-    var i = 0,
-        self = this,
-        iterator = {
-      next: function next() {
-        var done = self.length <= i;
-        return done ? { done: done } : { done: done, value: self[i++] };
+    try {
+      setDescriptor = create(defineProperty({}, prefix, {
+        get: function () {
+          return defineProperty(this, prefix, { value: false })[prefix];
+        }
+      }))[prefix] || defineProperty;
+    } catch (o_O) {
+      setDescriptor = function (o, key, descriptor) {
+        var protoDescriptor = gOPD(ObjectProto, key);
+        delete ObjectProto[key];
+        defineProperty(o, key, descriptor);
+        defineProperty(ObjectProto, key, protoDescriptor);
+      };
+    }
+  })(Object, 'getOwnPropertySymbols');
+
+  (function (O, S) {
+    var dP = O.defineProperty,
+        ObjectProto = O.prototype,
+        toString = ObjectProto.toString,
+        toStringTag = 'toStringTag',
+        descriptor;
+    ['iterator', 'match', 'replace', 'search', 'split', 'hasInstance', 'isConcatSpreadable', 'unscopables', 'species', 'toPrimitive', toStringTag].forEach(function (name) {
+      if (!(name in Symbol)) {
+        dP(Symbol, name, { value: Symbol(name) });
+        switch (name) {
+          case toStringTag:
+            descriptor = O.getOwnPropertyDescriptor(ObjectProto, 'toString');
+            descriptor.value = function () {
+              var str = toString.call(this),
+                  tst = typeof this === 'undefined' || this === null ? undefined : this[Symbol.toStringTag];
+              return typeof tst === 'undefined' ? str : '[object ' + tst + ']';
+            };
+            dP(ObjectProto, 'toString', descriptor);
+            break;
+        }
       }
+    });
+  })(Object, Symbol);
+
+  (function (Si, AP, SP) {
+
+    function returnThis() {
+      return this;
+    }
+
+    if (!AP[Si]) AP[Si] = function () {
+      var i = 0,
+          self = this,
+          iterator = {
+        next: function next() {
+          var done = self.length <= i;
+          return done ? { done: done } : { done: done, value: self[i++] };
+        }
+      };
+      iterator[Si] = returnThis;
+      return iterator;
     };
-    iterator[Si] = returnThis;
-    return iterator;
-  };
 
-  if (!SP[Si]) SP[Si] = function () {
-    var fromCodePoint = String.fromCodePoint,
-        self = this,
-        i = 0,
-        length = self.length,
-        iterator = {
-      next: function next() {
-        var done = length <= i,
-            c = done ? '' : fromCodePoint(self.codePointAt(i));
-        i += c.length;
-        return done ? { done: done } : { done: done, value: c };
-      }
+    if (!SP[Si]) SP[Si] = function () {
+      var fromCodePoint = String.fromCodePoint,
+          self = this,
+          i = 0,
+          length = self.length,
+          iterator = {
+        next: function next() {
+          var done = length <= i,
+              c = done ? '' : fromCodePoint(self.codePointAt(i));
+          i += c.length;
+          return done ? { done: done } : { done: done, value: c };
+        }
+      };
+      iterator[Si] = returnThis;
+      return iterator;
     };
-    iterator[Si] = returnThis;
-    return iterator;
+  })(Symbol.iterator, Array.prototype, String.prototype);
+}
+
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
+  Number.isNaN = Number.isNaN || function (value) {
+    return value !== value;
   };
-})(Symbol.iterator, Array.prototype, String.prototype);
 
-Number.isNaN = Number.isNaN || function (value) {
-  return value !== value;
-};
+  Number.isFinite = Number.isFinite || function (value) {
+    return typeof value === "number" && isFinite(value);
+  };
+}
 
-Number.isFinite = Number.isFinite || function (value) {
-  return typeof value === "number" && isFinite(value);
-};
 if (!String.prototype.endsWith || function () {
   try {
     return !"ab".endsWith("a", 1);
@@ -291,109 +298,112 @@ if (!String.prototype.startsWith || function () {
   };
 }
 
-if (!Array.from) {
-  Array.from = function () {
-    var toInteger = function (it) {
-      return isNaN(it = +it) ? 0 : (it > 0 ? Math.floor : Math.ceil)(it);
-    };
-    var toLength = function (it) {
-      return it > 0 ? Math.min(toInteger(it), 0x1fffffffffffff) : 0;
-    };
-    var iterCall = function (iter, fn, val, index) {
-      try {
-        return fn(val, index);
-      } catch (E) {
-        if (typeof iter.return == 'function') iter.return();
-        throw E;
-      }
-    };
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-    return function from(arrayLike) {
-      var O = Object(arrayLike),
-          C = typeof this == 'function' ? this : Array,
-          aLen = arguments.length,
-          mapfn = aLen > 1 ? arguments[1] : undefined,
-          mapping = mapfn !== undefined,
-          index = 0,
-          iterFn = O[Symbol.iterator],
-          length,
-          result,
-          step,
-          iterator;
-      if (mapping) mapfn = mapfn.bind(aLen > 2 ? arguments[2] : undefined);
-      if (iterFn != undefined && !Array.isArray(arrayLike)) {
-        for (iterator = iterFn.call(O), result = new C(); !(step = iterator.next()).done; index++) {
-          result[index] = mapping ? iterCall(iterator, mapfn, step.value, index) : step.value;
+  if (!Array.from) {
+    Array.from = function () {
+      var toInteger = function (it) {
+        return isNaN(it = +it) ? 0 : (it > 0 ? Math.floor : Math.ceil)(it);
+      };
+      var toLength = function (it) {
+        return it > 0 ? Math.min(toInteger(it), 0x1fffffffffffff) : 0;
+      };
+      var iterCall = function (iter, fn, val, index) {
+        try {
+          return fn(val, index);
+        } catch (E) {
+          if (typeof iter.return == 'function') iter.return();
+          throw E;
         }
-      } else {
-        length = toLength(O.length);
-        for (result = new C(length); length > index; index++) {
-          result[index] = mapping ? mapfn(O[index], index) : O[index];
+      };
+
+      return function from(arrayLike) {
+        var O = Object(arrayLike),
+            C = typeof this == 'function' ? this : Array,
+            aLen = arguments.length,
+            mapfn = aLen > 1 ? arguments[1] : undefined,
+            mapping = mapfn !== undefined,
+            index = 0,
+            iterFn = O[Symbol.iterator],
+            length,
+            result,
+            step,
+            iterator;
+        if (mapping) mapfn = mapfn.bind(aLen > 2 ? arguments[2] : undefined);
+        if (iterFn != undefined && !Array.isArray(arrayLike)) {
+          for (iterator = iterFn.call(O), result = new C(); !(step = iterator.next()).done; index++) {
+            result[index] = mapping ? iterCall(iterator, mapfn, step.value, index) : step.value;
+          }
+        } else {
+          length = toLength(O.length);
+          for (result = new C(length); length > index; index++) {
+            result[index] = mapping ? mapfn(O[index], index) : O[index];
+          }
         }
-      }
-      result.length = index;
-      return result;
-    };
-  }();
-}
+        result.length = index;
+        return result;
+      };
+    }();
+  }
 
-if (!Array.prototype.find) {
-  Object.defineProperty(Array.prototype, 'find', {
-    configurable: true,
-    writable: true,
-    enumerable: false,
-    value: function (predicate) {
-      if (this === null) {
-        throw new TypeError('Array.prototype.find called on null or undefined');
-      }
-      if (typeof predicate !== 'function') {
-        throw new TypeError('predicate must be a function');
-      }
-      var list = Object(this);
-      var length = list.length >>> 0;
-      var thisArg = arguments[1];
-      var value;
-
-      for (var i = 0; i < length; i++) {
-        value = list[i];
-        if (predicate.call(thisArg, value, i, list)) {
-          return value;
+  if (!Array.prototype.find) {
+    Object.defineProperty(Array.prototype, 'find', {
+      configurable: true,
+      writable: true,
+      enumerable: false,
+      value: function (predicate) {
+        if (this === null) {
+          throw new TypeError('Array.prototype.find called on null or undefined');
+        }
+        if (typeof predicate !== 'function') {
+          throw new TypeError('predicate must be a function');
         }
+        var list = Object(this);
+        var length = list.length >>> 0;
+        var thisArg = arguments[1];
+        var value;
+
+        for (var i = 0; i < length; i++) {
+          value = list[i];
+          if (predicate.call(thisArg, value, i, list)) {
+            return value;
+          }
+        }
+        return undefined;
       }
-      return undefined;
-    }
-  });
-}
+    });
+  }
 
-if (!Array.prototype.findIndex) {
-  Object.defineProperty(Array.prototype, 'findIndex', {
-    configurable: true,
-    writable: true,
-    enumerable: false,
-    value: function (predicate) {
-      if (this === null) {
-        throw new TypeError('Array.prototype.findIndex called on null or undefined');
-      }
-      if (typeof predicate !== 'function') {
-        throw new TypeError('predicate must be a function');
-      }
-      var list = Object(this);
-      var length = list.length >>> 0;
-      var thisArg = arguments[1];
-      var value;
-
-      for (var i = 0; i < length; i++) {
-        value = list[i];
-        if (predicate.call(thisArg, value, i, list)) {
-          return i;
+  if (!Array.prototype.findIndex) {
+    Object.defineProperty(Array.prototype, 'findIndex', {
+      configurable: true,
+      writable: true,
+      enumerable: false,
+      value: function (predicate) {
+        if (this === null) {
+          throw new TypeError('Array.prototype.findIndex called on null or undefined');
         }
+        if (typeof predicate !== 'function') {
+          throw new TypeError('predicate must be a function');
+        }
+        var list = Object(this);
+        var length = list.length >>> 0;
+        var thisArg = arguments[1];
+        var value;
+
+        for (var i = 0; i < length; i++) {
+          value = list[i];
+          if (predicate.call(thisArg, value, i, list)) {
+            return i;
+          }
+        }
+        return -1;
       }
-      return -1;
-    }
-  });
+    });
+  }
 }
 
-if (!Array.prototype.includes) {
+if (typeof FEATURE_NO_ES2016 === 'undefined' && !Array.prototype.includes) {
   Object.defineProperty(Array.prototype, 'includes', {
     configurable: true,
     writable: true,
@@ -427,376 +437,389 @@ if (!Array.prototype.includes) {
   });
 }
 
-(function () {
-  let needsFix = false;
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-  try {
-    let s = Object.keys('a');
-    needsFix = s.length !== 1 || s[0] !== '0';
-  } catch (e) {
-    needsFix = true;
-  }
+  (function () {
+    let needsFix = false;
 
-  if (needsFix) {
-    Object.keys = function () {
-      var hasOwnProperty = Object.prototype.hasOwnProperty,
-          hasDontEnumBug = !{ toString: null }.propertyIsEnumerable('toString'),
-          dontEnums = ['toString', 'toLocaleString', 'valueOf', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable', 'constructor'],
-          dontEnumsLength = dontEnums.length;
+    try {
+      let s = Object.keys('a');
+      needsFix = s.length !== 1 || s[0] !== '0';
+    } catch (e) {
+      needsFix = true;
+    }
 
-      return function (obj) {
-        if (obj === undefined || obj === null) {
-          throw TypeError(`Cannot convert undefined or null to object`);
-        }
+    if (needsFix) {
+      Object.keys = function () {
+        var hasOwnProperty = Object.prototype.hasOwnProperty,
+            hasDontEnumBug = !{ toString: null }.propertyIsEnumerable('toString'),
+            dontEnums = ['toString', 'toLocaleString', 'valueOf', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable', 'constructor'],
+            dontEnumsLength = dontEnums.length;
 
-        obj = Object(obj);
+        return function (obj) {
+          if (obj === undefined || obj === null) {
+            throw TypeError(`Cannot convert undefined or null to object`);
+          }
+
+          obj = Object(obj);
 
-        var result = [],
-            prop,
-            i;
+          var result = [],
+              prop,
+              i;
 
-        for (prop in obj) {
-          if (hasOwnProperty.call(obj, prop)) {
-            result.push(prop);
+          for (prop in obj) {
+            if (hasOwnProperty.call(obj, prop)) {
+              result.push(prop);
+            }
           }
-        }
 
-        if (hasDontEnumBug) {
-          for (i = 0; i < dontEnumsLength; i++) {
-            if (hasOwnProperty.call(obj, dontEnums[i])) {
-              result.push(dontEnums[i]);
+          if (hasDontEnumBug) {
+            for (i = 0; i < dontEnumsLength; i++) {
+              if (hasOwnProperty.call(obj, dontEnums[i])) {
+                result.push(dontEnums[i]);
+              }
             }
           }
-        }
 
-        return result;
-      };
-    }();
-  }
-})();
+          return result;
+        };
+      }();
+    }
+  })();
 
-(function (O) {
-  if ('assign' in O) {
-    return;
-  }
+  (function (O) {
+    if ('assign' in O) {
+      return;
+    }
 
-  O.defineProperty(O, 'assign', {
-    configurable: true,
-    writable: true,
-    value: function () {
-      var gOPS = O.getOwnPropertySymbols,
-          pIE = O.propertyIsEnumerable,
-          filterOS = gOPS ? function (self) {
-        return gOPS(self).filter(pIE, self);
-      } : function () {
-        return Array.prototype;
-      };
+    O.defineProperty(O, 'assign', {
+      configurable: true,
+      writable: true,
+      value: function () {
+        var gOPS = O.getOwnPropertySymbols,
+            pIE = O.propertyIsEnumerable,
+            filterOS = gOPS ? function (self) {
+          return gOPS(self).filter(pIE, self);
+        } : function () {
+          return Array.prototype;
+        };
+
+        return function assign(where) {
+          if (gOPS && !(where instanceof O)) {
+            console.warn('problematic Symbols', where);
+          }
 
-      return function assign(where) {
-        if (gOPS && !(where instanceof O)) {
-          console.warn('problematic Symbols', where);
-        }
+          function set(keyOrSymbol) {
+            where[keyOrSymbol] = arg[keyOrSymbol];
+          }
 
-        function set(keyOrSymbol) {
-          where[keyOrSymbol] = arg[keyOrSymbol];
-        }
+          for (var i = 1, ii = arguments.length; i < ii; ++i) {
+            var arg = arguments[i];
 
-        for (var i = 1, ii = arguments.length; i < ii; ++i) {
-          var arg = arguments[i];
+            if (arg === null || arg === undefined) {
+              continue;
+            }
 
-          if (arg === null || arg === undefined) {
-            continue;
+            O.keys(arg).concat(filterOS(arg)).forEach(set);
           }
 
-          O.keys(arg).concat(filterOS(arg)).forEach(set);
-        }
+          return where;
+        };
+      }()
+    });
+  })(Object);
+}
 
-        return where;
-      };
-    }()
-  });
-})(Object);
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-(function (global) {
-  var i;
+  (function (global) {
+    var i;
 
-  var defineProperty = Object.defineProperty,
-      is = function (a, b) {
-    return a === b || a !== a && b !== b;
-  };
+    var defineProperty = Object.defineProperty,
+        is = function (a, b) {
+      return a === b || a !== a && b !== b;
+    };
 
-  if (typeof WeakMap == 'undefined') {
-    global.WeakMap = createCollection({
-      'delete': sharedDelete,
+    if (typeof WeakMap == 'undefined') {
+      global.WeakMap = createCollection({
+        'delete': sharedDelete,
 
-      clear: sharedClear,
+        clear: sharedClear,
 
-      get: sharedGet,
+        get: sharedGet,
 
-      has: mapHas,
+        has: mapHas,
 
-      set: sharedSet
-    }, true);
-  }
+        set: sharedSet
+      }, true);
+    }
 
-  if (typeof Map == 'undefined' || typeof new Map().values !== 'function' || !new Map().values().next) {
-    global.Map = createCollection({
-      'delete': sharedDelete,
+    if (typeof Map == 'undefined' || typeof new Map().values !== 'function' || !new Map().values().next) {
+      global.Map = createCollection({
+        'delete': sharedDelete,
 
-      has: mapHas,
+        has: mapHas,
 
-      get: sharedGet,
+        get: sharedGet,
 
-      set: sharedSet,
+        set: sharedSet,
 
-      keys: sharedKeys,
+        keys: sharedKeys,
 
-      values: sharedValues,
+        values: sharedValues,
 
-      entries: mapEntries,
+        entries: mapEntries,
 
-      forEach: sharedForEach,
+        forEach: sharedForEach,
 
-      clear: sharedClear,
+        clear: sharedClear,
 
-      [Symbol.iterator]: mapEntries
-    });
-  }
+        [Symbol.iterator]: mapEntries
+      });
+    }
 
-  if (typeof Set == 'undefined' || typeof new Set().values !== 'function' || !new Set().values().next) {
-    global.Set = createCollection({
-      has: setHas,
+    if (typeof Set == 'undefined' || typeof new Set().values !== 'function' || !new Set().values().next) {
+      global.Set = createCollection({
+        has: setHas,
 
-      add: sharedAdd,
+        add: sharedAdd,
 
-      'delete': sharedDelete,
+        'delete': sharedDelete,
 
-      clear: sharedClear,
+        clear: sharedClear,
 
-      keys: sharedValues,
-      values: sharedValues,
+        keys: sharedValues,
+        values: sharedValues,
 
-      entries: setEntries,
+        entries: setEntries,
 
-      forEach: sharedForEach,
+        forEach: sharedForEach,
 
-      [Symbol.iterator]: sharedValues
-    });
-  }
+        [Symbol.iterator]: sharedValues
+      });
+    }
 
-  if (typeof WeakSet == 'undefined') {
-    global.WeakSet = createCollection({
-      'delete': sharedDelete,
+    if (typeof WeakSet == 'undefined') {
+      global.WeakSet = createCollection({
+        'delete': sharedDelete,
 
-      add: sharedAdd,
+        add: sharedAdd,
 
-      clear: sharedClear,
+        clear: sharedClear,
 
-      has: setHas
-    }, true);
-  }
+        has: setHas
+      }, true);
+    }
+
+    function createCollection(proto, objectOnly) {
+      function Collection(a) {
+        if (!this || this.constructor !== Collection) return new Collection(a);
+        this._keys = [];
+        this._values = [];
+        this._itp = [];
+        this.objectOnly = objectOnly;
+
+        if (a) init.call(this, a);
+      }
+
+      if (!objectOnly) {
+        defineProperty(proto, 'size', {
+          get: sharedSize
+        });
+      }
 
-  function createCollection(proto, objectOnly) {
-    function Collection(a) {
-      if (!this || this.constructor !== Collection) return new Collection(a);
-      this._keys = [];
-      this._values = [];
-      this._itp = [];
-      this.objectOnly = objectOnly;
+      proto.constructor = Collection;
+      Collection.prototype = proto;
 
-      if (a) init.call(this, a);
+      return Collection;
     }
 
-    if (!objectOnly) {
-      defineProperty(proto, 'size', {
-        get: sharedSize
-      });
+    function init(a) {
+      var i;
+
+      if (this.add) a.forEach(this.add, this);else a.forEach(function (a) {
+          this.set(a[0], a[1]);
+        }, this);
     }
 
-    proto.constructor = Collection;
-    Collection.prototype = proto;
+    function sharedDelete(key) {
+      if (this.has(key)) {
+        this._keys.splice(i, 1);
+        this._values.splice(i, 1);
 
-    return Collection;
-  }
+        this._itp.forEach(function (p) {
+          if (i < p[0]) p[0]--;
+        });
+      }
 
-  function init(a) {
-    var i;
+      return -1 < i;
+    };
 
-    if (this.add) a.forEach(this.add, this);else a.forEach(function (a) {
-        this.set(a[0], a[1]);
-      }, this);
-  }
+    function sharedGet(key) {
+      return this.has(key) ? this._values[i] : undefined;
+    }
 
-  function sharedDelete(key) {
-    if (this.has(key)) {
-      this._keys.splice(i, 1);
-      this._values.splice(i, 1);
+    function has(list, key) {
+      if (this.objectOnly && key !== Object(key)) throw new TypeError("Invalid value used as weak collection key");
 
-      this._itp.forEach(function (p) {
-        if (i < p[0]) p[0]--;
-      });
+      if (key != key || key === 0) for (i = list.length; i-- && !is(list[i], key);) {} else i = list.indexOf(key);
+      return -1 < i;
     }
 
-    return -1 < i;
-  };
+    function setHas(value) {
+      return has.call(this, this._values, value);
+    }
 
-  function sharedGet(key) {
-    return this.has(key) ? this._values[i] : undefined;
-  }
+    function mapHas(value) {
+      return has.call(this, this._keys, value);
+    }
 
-  function has(list, key) {
-    if (this.objectOnly && key !== Object(key)) throw new TypeError("Invalid value used as weak collection key");
+    function sharedSet(key, value) {
+      this.has(key) ? this._values[i] = value : this._values[this._keys.push(key) - 1] = value;
+      return this;
+    }
 
-    if (key != key || key === 0) for (i = list.length; i-- && !is(list[i], key);) {} else i = list.indexOf(key);
-    return -1 < i;
-  }
+    function sharedAdd(value) {
+      if (!this.has(value)) this._values.push(value);
+      return this;
+    }
 
-  function setHas(value) {
-    return has.call(this, this._values, value);
-  }
+    function sharedClear() {
+      (this._keys || 0).length = this._values.length = 0;
+    }
 
-  function mapHas(value) {
-    return has.call(this, this._keys, value);
-  }
+    function sharedKeys() {
+      return sharedIterator(this._itp, this._keys);
+    }
 
-  function sharedSet(key, value) {
-    this.has(key) ? this._values[i] = value : this._values[this._keys.push(key) - 1] = value;
-    return this;
-  }
+    function sharedValues() {
+      return sharedIterator(this._itp, this._values);
+    }
 
-  function sharedAdd(value) {
-    if (!this.has(value)) this._values.push(value);
-    return this;
-  }
+    function mapEntries() {
+      return sharedIterator(this._itp, this._keys, this._values);
+    }
 
-  function sharedClear() {
-    (this._keys || 0).length = this._values.length = 0;
-  }
+    function setEntries() {
+      return sharedIterator(this._itp, this._values, this._values);
+    }
 
-  function sharedKeys() {
-    return sharedIterator(this._itp, this._keys);
-  }
+    function sharedIterator(itp, array, array2) {
+      var p = [0],
+          done = false;
+      itp.push(p);
+      return {
+        [Symbol.iterator]: function () {
+          return this;
+        },
+        next: function () {
+          var v,
+              k = p[0];
+          if (!done && k < array.length) {
+            v = array2 ? [array[k], array2[k]] : array[k];
+            p[0]++;
+          } else {
+            done = true;
+            itp.splice(itp.indexOf(p), 1);
+          }
+          return { done: done, value: v };
+        }
+      };
+    }
 
-  function sharedValues() {
-    return sharedIterator(this._itp, this._values);
-  }
+    function sharedSize() {
+      return this._values.length;
+    }
 
-  function mapEntries() {
-    return sharedIterator(this._itp, this._keys, this._values);
-  }
+    function sharedForEach(callback, context) {
+      var it = this.entries();
+      for (;;) {
+        var r = it.next();
+        if (r.done) break;
+        callback.call(context, r.value[1], r.value[0], this);
+      }
+    }
+  })(PLATFORM.global);
+}
+
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-  function setEntries() {
-    return sharedIterator(this._itp, this._values, this._values);
+  const bind = Function.prototype.bind;
+
+  if (typeof PLATFORM.global.Reflect === 'undefined') {
+    PLATFORM.global.Reflect = {};
   }
 
-  function sharedIterator(itp, array, array2) {
-    var p = [0],
-        done = false;
-    itp.push(p);
-    return {
-      [Symbol.iterator]: function () {
-        return this;
-      },
-      next: function () {
-        var v,
-            k = p[0];
-        if (!done && k < array.length) {
-          v = array2 ? [array[k], array2[k]] : array[k];
-          p[0]++;
-        } else {
-          done = true;
-          itp.splice(itp.indexOf(p), 1);
-        }
-        return { done: done, value: v };
+  if (typeof Reflect.defineProperty !== 'function') {
+    Reflect.defineProperty = function (target, propertyKey, descriptor) {
+      if (typeof target === 'object' ? target === null : typeof target !== 'function') {
+        throw new TypeError('Reflect.defineProperty called on non-object');
+      }
+      try {
+        Object.defineProperty(target, propertyKey, descriptor);
+        return true;
+      } catch (e) {
+        return false;
       }
     };
   }
 
-  function sharedSize() {
-    return this._values.length;
-  }
+  if (typeof Reflect.construct !== 'function') {
+    Reflect.construct = function (Target, args) {
+      if (args) {
+        switch (args.length) {
+          case 0:
+            return new Target();
+          case 1:
+            return new Target(args[0]);
+          case 2:
+            return new Target(args[0], args[1]);
+          case 3:
+            return new Target(args[0], args[1], args[2]);
+          case 4:
+            return new Target(args[0], args[1], args[2], args[3]);
+        }
+      }
 
-  function sharedForEach(callback, context) {
-    var it = this.entries();
-    for (;;) {
-      var r = it.next();
-      if (r.done) break;
-      callback.call(context, r.value[1], r.value[0], this);
-    }
+      var a = [null];
+      a.push.apply(a, args);
+      return new (bind.apply(Target, a))();
+    };
   }
-})(PLATFORM.global);
 
-const emptyMetadata = Object.freeze({});
-const metadataContainerKey = '__metadata__';
-const bind = Function.prototype.bind;
-
-if (typeof PLATFORM.global.Reflect === 'undefined') {
-  PLATFORM.global.Reflect = {};
-}
-
-if (typeof Reflect.getOwnMetadata !== 'function') {
-  Reflect.getOwnMetadata = function (metadataKey, target, targetKey) {
-    if (target.hasOwnProperty(metadataContainerKey)) {
-      return (target[metadataContainerKey][targetKey] || emptyMetadata)[metadataKey];
-    }
-  };
-}
-
-if (typeof Reflect.defineMetadata !== 'function') {
-  Reflect.defineMetadata = function (metadataKey, metadataValue, target, targetKey) {
-    let metadataContainer = target.hasOwnProperty(metadataContainerKey) ? target[metadataContainerKey] : target[metadataContainerKey] = {};
-    let targetContainer = metadataContainer[targetKey] || (metadataContainer[targetKey] = {});
-    targetContainer[metadataKey] = metadataValue;
-  };
-}
-
-if (typeof Reflect.metadata !== 'function') {
-  Reflect.metadata = function (metadataKey, metadataValue) {
-    return function (target, targetKey) {
-      Reflect.defineMetadata(metadataKey, metadataValue, target, targetKey);
+  if (typeof Reflect.ownKeys !== 'function') {
+    Reflect.ownKeys = function (o) {
+      return Object.getOwnPropertyNames(o).concat(Object.getOwnPropertySymbols(o));
     };
-  };
+  }
 }
 
-if (typeof Reflect.defineProperty !== 'function') {
-  Reflect.defineProperty = function (target, propertyKey, descriptor) {
-    if (typeof target === 'object' ? target === null : typeof target !== 'function') {
-      throw new TypeError('Reflect.defineProperty called on non-object');
-    }
-    try {
-      Object.defineProperty(target, propertyKey, descriptor);
-      return true;
-    } catch (e) {
-      return false;
-    }
-  };
-}
+if (typeof FEATURE_NO_ESNEXT === 'undefined') {
+
+  const emptyMetadata = Object.freeze({});
+  const metadataContainerKey = '__metadata__';
 
-if (typeof Reflect.construct !== 'function') {
-  Reflect.construct = function (Target, args) {
-    if (args) {
-      switch (args.length) {
-        case 0:
-          return new Target();
-        case 1:
-          return new Target(args[0]);
-        case 2:
-          return new Target(args[0], args[1]);
-        case 3:
-          return new Target(args[0], args[1], args[2]);
-        case 4:
-          return new Target(args[0], args[1], args[2], args[3]);
+  if (typeof Reflect.getOwnMetadata !== 'function') {
+    Reflect.getOwnMetadata = function (metadataKey, target, targetKey) {
+      if (target.hasOwnProperty(metadataContainerKey)) {
+        return (target[metadataContainerKey][targetKey] || emptyMetadata)[metadataKey];
       }
-    }
+    };
+  }
 
-    var a = [null];
-    a.push.apply(a, args);
-    return new (bind.apply(Target, a))();
-  };
-}
+  if (typeof Reflect.defineMetadata !== 'function') {
+    Reflect.defineMetadata = function (metadataKey, metadataValue, target, targetKey) {
+      let metadataContainer = target.hasOwnProperty(metadataContainerKey) ? target[metadataContainerKey] : target[metadataContainerKey] = {};
+      let targetContainer = metadataContainer[targetKey] || (metadataContainer[targetKey] = {});
+      targetContainer[metadataKey] = metadataValue;
+    };
+  }
 
-if (typeof Reflect.ownKeys !== 'function') {
-  Reflect.ownKeys = function (o) {
-    return Object.getOwnPropertyNames(o).concat(Object.getOwnPropertySymbols(o));
-  };
+  if (typeof Reflect.metadata !== 'function') {
+    Reflect.metadata = function (metadataKey, metadataValue) {
+      return function (target, targetKey) {
+        Reflect.defineMetadata(metadataKey, metadataValue, target, targetKey);
+      };
+    };
+  }
 }
\ No newline at end of file
diff --git a/dist/native-modules/aurelia-polyfills.js b/dist/native-modules/aurelia-polyfills.js
index 504848a..95e52e8 100644
--- a/dist/native-modules/aurelia-polyfills.js
+++ b/dist/native-modules/aurelia-polyfills.js
@@ -2,266 +2,273 @@ var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol
 
 import { PLATFORM } from 'aurelia-pal';
 
-(function (Object, GOPS) {
-  'use strict';
-
-  if (GOPS in Object) return;
-
-  var setDescriptor,
-      G = PLATFORM.global,
-      id = 0,
-      random = '' + Math.random(),
-      prefix = '__\x01symbol:',
-      prefixLength = prefix.length,
-      internalSymbol = '__\x01symbol@@' + random,
-      DP = 'defineProperty',
-      DPies = 'defineProperties',
-      GOPN = 'getOwnPropertyNames',
-      GOPD = 'getOwnPropertyDescriptor',
-      PIE = 'propertyIsEnumerable',
-      gOPN = Object[GOPN],
-      gOPD = Object[GOPD],
-      create = Object.create,
-      keys = Object.keys,
-      defineProperty = Object[DP],
-      $defineProperties = Object[DPies],
-      descriptor = gOPD(Object, GOPN),
-      ObjectProto = Object.prototype,
-      hOP = ObjectProto.hasOwnProperty,
-      pIE = ObjectProto[PIE],
-      toString = ObjectProto.toString,
-      indexOf = Array.prototype.indexOf || function (v) {
-    for (var i = this.length; i-- && this[i] !== v;) {}
-    return i;
-  },
-      addInternalIfNeeded = function addInternalIfNeeded(o, uid, enumerable) {
-    if (!hOP.call(o, internalSymbol)) {
-      defineProperty(o, internalSymbol, {
-        enumerable: false,
-        configurable: false,
-        writable: false,
-        value: {}
-      });
-    }
-    o[internalSymbol]['@@' + uid] = enumerable;
-  },
-      createWithSymbols = function createWithSymbols(proto, descriptors) {
-    var self = create(proto);
-    gOPN(descriptors).forEach(function (key) {
-      if (propertyIsEnumerable.call(descriptors, key)) {
-        $defineProperty(self, key, descriptors[key]);
-      }
-    });
-    return self;
-  },
-      copyAsNonEnumerable = function copyAsNonEnumerable(descriptor) {
-    var newDescriptor = create(descriptor);
-    newDescriptor.enumerable = false;
-    return newDescriptor;
-  },
-      get = function get() {},
-      onlyNonSymbols = function onlyNonSymbols(name) {
-    return name != internalSymbol && !hOP.call(source, name);
-  },
-      onlySymbols = function onlySymbols(name) {
-    return name != internalSymbol && hOP.call(source, name);
-  },
-      propertyIsEnumerable = function propertyIsEnumerable(key) {
-    var uid = '' + key;
-    return onlySymbols(uid) ? hOP.call(this, uid) && this[internalSymbol]['@@' + uid] : pIE.call(this, key);
-  },
-      setAndGetSymbol = function setAndGetSymbol(uid) {
-    var descriptor = {
-      enumerable: false,
-      configurable: true,
-      get: get,
-      set: function set(value) {
-        setDescriptor(this, uid, {
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
+  (function (Object, GOPS) {
+    'use strict';
+
+    if (GOPS in Object) return;
+
+    var setDescriptor,
+        G = PLATFORM.global,
+        id = 0,
+        random = '' + Math.random(),
+        prefix = '__\x01symbol:',
+        prefixLength = prefix.length,
+        internalSymbol = '__\x01symbol@@' + random,
+        DP = 'defineProperty',
+        DPies = 'defineProperties',
+        GOPN = 'getOwnPropertyNames',
+        GOPD = 'getOwnPropertyDescriptor',
+        PIE = 'propertyIsEnumerable',
+        gOPN = Object[GOPN],
+        gOPD = Object[GOPD],
+        create = Object.create,
+        keys = Object.keys,
+        defineProperty = Object[DP],
+        $defineProperties = Object[DPies],
+        descriptor = gOPD(Object, GOPN),
+        ObjectProto = Object.prototype,
+        hOP = ObjectProto.hasOwnProperty,
+        pIE = ObjectProto[PIE],
+        toString = ObjectProto.toString,
+        indexOf = Array.prototype.indexOf || function (v) {
+      for (var i = this.length; i-- && this[i] !== v;) {}
+      return i;
+    },
+        addInternalIfNeeded = function addInternalIfNeeded(o, uid, enumerable) {
+      if (!hOP.call(o, internalSymbol)) {
+        defineProperty(o, internalSymbol, {
           enumerable: false,
-          configurable: true,
-          writable: true,
-          value: value
+          configurable: false,
+          writable: false,
+          value: {}
         });
-        addInternalIfNeeded(this, uid, true);
       }
-    };
-    defineProperty(ObjectProto, uid, descriptor);
-    return source[uid] = defineProperty(Object(uid), 'constructor', sourceConstructor);
-  },
-      _Symbol = function _Symbol2(description) {
-    if (this && this !== G) {
-      throw new TypeError('Symbol is not a constructor');
-    }
-    return setAndGetSymbol(prefix.concat(description || '', random, ++id));
-  },
-      source = create(null),
-      sourceConstructor = { value: _Symbol },
-      sourceMap = function sourceMap(uid) {
-    return source[uid];
-  },
-      $defineProperty = function defineProp(o, key, descriptor) {
-    var uid = '' + key;
-    if (onlySymbols(uid)) {
-      setDescriptor(o, uid, descriptor.enumerable ? copyAsNonEnumerable(descriptor) : descriptor);
-      addInternalIfNeeded(o, uid, !!descriptor.enumerable);
-    } else {
-      defineProperty(o, key, descriptor);
-    }
-    return o;
-  },
-      $getOwnPropertySymbols = function getOwnPropertySymbols(o) {
-    var cof = toString.call(o);
-    o = cof === '[object String]' ? o.split('') : Object(o);
-    return gOPN(o).filter(onlySymbols).map(sourceMap);
-  };
-
-  descriptor.value = $defineProperty;
-  defineProperty(Object, DP, descriptor);
-
-  descriptor.value = $getOwnPropertySymbols;
-  defineProperty(Object, GOPS, descriptor);
-
-  descriptor.value = function getOwnPropertyNames(o) {
-    return gOPN(o).filter(onlyNonSymbols);
-  };
-  defineProperty(Object, GOPN, descriptor);
-
-  descriptor.value = function defineProperties(o, descriptors) {
-    var symbols = $getOwnPropertySymbols(descriptors);
-    if (symbols.length) {
-      keys(descriptors).concat(symbols).forEach(function (uid) {
-        if (propertyIsEnumerable.call(descriptors, uid)) {
-          $defineProperty(o, uid, descriptors[uid]);
+      o[internalSymbol]['@@' + uid] = enumerable;
+    },
+        createWithSymbols = function createWithSymbols(proto, descriptors) {
+      var self = create(proto);
+      gOPN(descriptors).forEach(function (key) {
+        if (propertyIsEnumerable.call(descriptors, key)) {
+          $defineProperty(self, key, descriptors[key]);
         }
       });
-    } else {
-      $defineProperties(o, descriptors);
-    }
-    return o;
-  };
-  defineProperty(Object, DPies, descriptor);
+      return self;
+    },
+        copyAsNonEnumerable = function copyAsNonEnumerable(descriptor) {
+      var newDescriptor = create(descriptor);
+      newDescriptor.enumerable = false;
+      return newDescriptor;
+    },
+        get = function get() {},
+        onlyNonSymbols = function onlyNonSymbols(name) {
+      return name != internalSymbol && !hOP.call(source, name);
+    },
+        onlySymbols = function onlySymbols(name) {
+      return name != internalSymbol && hOP.call(source, name);
+    },
+        propertyIsEnumerable = function propertyIsEnumerable(key) {
+      var uid = '' + key;
+      return onlySymbols(uid) ? hOP.call(this, uid) && this[internalSymbol]['@@' + uid] : pIE.call(this, key);
+    },
+        setAndGetSymbol = function setAndGetSymbol(uid) {
+      var descriptor = {
+        enumerable: false,
+        configurable: true,
+        get: get,
+        set: function set(value) {
+          setDescriptor(this, uid, {
+            enumerable: false,
+            configurable: true,
+            writable: true,
+            value: value
+          });
+          addInternalIfNeeded(this, uid, true);
+        }
+      };
+      defineProperty(ObjectProto, uid, descriptor);
+      return source[uid] = defineProperty(Object(uid), 'constructor', sourceConstructor);
+    },
+        _Symbol = function _Symbol2(description) {
+      if (this && this !== G) {
+        throw new TypeError('Symbol is not a constructor');
+      }
+      return setAndGetSymbol(prefix.concat(description || '', random, ++id));
+    },
+        source = create(null),
+        sourceConstructor = { value: _Symbol },
+        sourceMap = function sourceMap(uid) {
+      return source[uid];
+    },
+        $defineProperty = function defineProp(o, key, descriptor) {
+      var uid = '' + key;
+      if (onlySymbols(uid)) {
+        setDescriptor(o, uid, descriptor.enumerable ? copyAsNonEnumerable(descriptor) : descriptor);
+        addInternalIfNeeded(o, uid, !!descriptor.enumerable);
+      } else {
+        defineProperty(o, key, descriptor);
+      }
+      return o;
+    },
+        $getOwnPropertySymbols = function getOwnPropertySymbols(o) {
+      var cof = toString.call(o);
+      o = cof === '[object String]' ? o.split('') : Object(o);
+      return gOPN(o).filter(onlySymbols).map(sourceMap);
+    };
 
-  descriptor.value = propertyIsEnumerable;
-  defineProperty(ObjectProto, PIE, descriptor);
+    descriptor.value = $defineProperty;
+    defineProperty(Object, DP, descriptor);
 
-  descriptor.value = _Symbol;
-  defineProperty(G, 'Symbol', descriptor);
+    descriptor.value = $getOwnPropertySymbols;
+    defineProperty(Object, GOPS, descriptor);
 
-  descriptor.value = function (key) {
-    var uid = prefix.concat(prefix, key, random);
-    return uid in ObjectProto ? source[uid] : setAndGetSymbol(uid);
-  };
-  defineProperty(_Symbol, 'for', descriptor);
+    descriptor.value = function getOwnPropertyNames(o) {
+      return gOPN(o).filter(onlyNonSymbols);
+    };
+    defineProperty(Object, GOPN, descriptor);
+
+    descriptor.value = function defineProperties(o, descriptors) {
+      var symbols = $getOwnPropertySymbols(descriptors);
+      if (symbols.length) {
+        keys(descriptors).concat(symbols).forEach(function (uid) {
+          if (propertyIsEnumerable.call(descriptors, uid)) {
+            $defineProperty(o, uid, descriptors[uid]);
+          }
+        });
+      } else {
+        $defineProperties(o, descriptors);
+      }
+      return o;
+    };
+    defineProperty(Object, DPies, descriptor);
 
-  descriptor.value = function (symbol) {
-    return hOP.call(source, symbol) ? symbol.slice(prefixLength * 2, -random.length) : void 0;
-  };
-  defineProperty(_Symbol, 'keyFor', descriptor);
+    descriptor.value = propertyIsEnumerable;
+    defineProperty(ObjectProto, PIE, descriptor);
 
-  descriptor.value = function getOwnPropertyDescriptor(o, key) {
-    var descriptor = gOPD(o, key);
-    if (descriptor && onlySymbols(key)) {
-      descriptor.enumerable = propertyIsEnumerable.call(o, key);
-    }
-    return descriptor;
-  };
-  defineProperty(Object, GOPD, descriptor);
+    descriptor.value = _Symbol;
+    defineProperty(G, 'Symbol', descriptor);
 
-  descriptor.value = function (proto, descriptors) {
-    return arguments.length === 1 ? create(proto) : createWithSymbols(proto, descriptors);
-  };
-  defineProperty(Object, 'create', descriptor);
+    descriptor.value = function (key) {
+      var uid = prefix.concat(prefix, key, random);
+      return uid in ObjectProto ? source[uid] : setAndGetSymbol(uid);
+    };
+    defineProperty(_Symbol, 'for', descriptor);
 
-  descriptor.value = function () {
-    var str = toString.call(this);
-    return str === '[object String]' && onlySymbols(this) ? '[object Symbol]' : str;
-  };
-  defineProperty(ObjectProto, 'toString', descriptor);
+    descriptor.value = function (symbol) {
+      return hOP.call(source, symbol) ? symbol.slice(prefixLength * 2, -random.length) : void 0;
+    };
+    defineProperty(_Symbol, 'keyFor', descriptor);
 
-  try {
-    setDescriptor = create(defineProperty({}, prefix, {
-      get: function get() {
-        return defineProperty(this, prefix, { value: false })[prefix];
+    descriptor.value = function getOwnPropertyDescriptor(o, key) {
+      var descriptor = gOPD(o, key);
+      if (descriptor && onlySymbols(key)) {
+        descriptor.enumerable = propertyIsEnumerable.call(o, key);
       }
-    }))[prefix] || defineProperty;
-  } catch (o_O) {
-    setDescriptor = function setDescriptor(o, key, descriptor) {
-      var protoDescriptor = gOPD(ObjectProto, key);
-      delete ObjectProto[key];
-      defineProperty(o, key, descriptor);
-      defineProperty(ObjectProto, key, protoDescriptor);
+      return descriptor;
     };
-  }
-})(Object, 'getOwnPropertySymbols');
-
-(function (O, S) {
-  var dP = O.defineProperty,
-      ObjectProto = O.prototype,
-      toString = ObjectProto.toString,
-      toStringTag = 'toStringTag',
-      descriptor;
-  ['iterator', 'match', 'replace', 'search', 'split', 'hasInstance', 'isConcatSpreadable', 'unscopables', 'species', 'toPrimitive', toStringTag].forEach(function (name) {
-    if (!(name in Symbol)) {
-      dP(Symbol, name, { value: Symbol(name) });
-      switch (name) {
-        case toStringTag:
-          descriptor = O.getOwnPropertyDescriptor(ObjectProto, 'toString');
-          descriptor.value = function () {
-            var str = toString.call(this),
-                tst = typeof this === 'undefined' || this === null ? undefined : this[Symbol.toStringTag];
-            return typeof tst === 'undefined' ? str : '[object ' + tst + ']';
-          };
-          dP(ObjectProto, 'toString', descriptor);
-          break;
-      }
-    }
-  });
-})(Object, Symbol);
+    defineProperty(Object, GOPD, descriptor);
 
-(function (Si, AP, SP) {
+    descriptor.value = function (proto, descriptors) {
+      return arguments.length === 1 ? create(proto) : createWithSymbols(proto, descriptors);
+    };
+    defineProperty(Object, 'create', descriptor);
 
-  function returnThis() {
-    return this;
-  }
+    descriptor.value = function () {
+      var str = toString.call(this);
+      return str === '[object String]' && onlySymbols(this) ? '[object Symbol]' : str;
+    };
+    defineProperty(ObjectProto, 'toString', descriptor);
 
-  if (!AP[Si]) AP[Si] = function () {
-    var i = 0,
-        self = this,
-        iterator = {
-      next: function next() {
-        var done = self.length <= i;
-        return done ? { done: done } : { done: done, value: self[i++] };
+    try {
+      setDescriptor = create(defineProperty({}, prefix, {
+        get: function get() {
+          return defineProperty(this, prefix, { value: false })[prefix];
+        }
+      }))[prefix] || defineProperty;
+    } catch (o_O) {
+      setDescriptor = function setDescriptor(o, key, descriptor) {
+        var protoDescriptor = gOPD(ObjectProto, key);
+        delete ObjectProto[key];
+        defineProperty(o, key, descriptor);
+        defineProperty(ObjectProto, key, protoDescriptor);
+      };
+    }
+  })(Object, 'getOwnPropertySymbols');
+
+  (function (O, S) {
+    var dP = O.defineProperty,
+        ObjectProto = O.prototype,
+        toString = ObjectProto.toString,
+        toStringTag = 'toStringTag',
+        descriptor;
+    ['iterator', 'match', 'replace', 'search', 'split', 'hasInstance', 'isConcatSpreadable', 'unscopables', 'species', 'toPrimitive', toStringTag].forEach(function (name) {
+      if (!(name in Symbol)) {
+        dP(Symbol, name, { value: Symbol(name) });
+        switch (name) {
+          case toStringTag:
+            descriptor = O.getOwnPropertyDescriptor(ObjectProto, 'toString');
+            descriptor.value = function () {
+              var str = toString.call(this),
+                  tst = typeof this === 'undefined' || this === null ? undefined : this[Symbol.toStringTag];
+              return typeof tst === 'undefined' ? str : '[object ' + tst + ']';
+            };
+            dP(ObjectProto, 'toString', descriptor);
+            break;
+        }
       }
+    });
+  })(Object, Symbol);
+
+  (function (Si, AP, SP) {
+
+    function returnThis() {
+      return this;
+    }
+
+    if (!AP[Si]) AP[Si] = function () {
+      var i = 0,
+          self = this,
+          iterator = {
+        next: function next() {
+          var done = self.length <= i;
+          return done ? { done: done } : { done: done, value: self[i++] };
+        }
+      };
+      iterator[Si] = returnThis;
+      return iterator;
     };
-    iterator[Si] = returnThis;
-    return iterator;
-  };
 
-  if (!SP[Si]) SP[Si] = function () {
-    var fromCodePoint = String.fromCodePoint,
-        self = this,
-        i = 0,
-        length = self.length,
-        iterator = {
-      next: function next() {
-        var done = length <= i,
-            c = done ? '' : fromCodePoint(self.codePointAt(i));
-        i += c.length;
-        return done ? { done: done } : { done: done, value: c };
-      }
+    if (!SP[Si]) SP[Si] = function () {
+      var fromCodePoint = String.fromCodePoint,
+          self = this,
+          i = 0,
+          length = self.length,
+          iterator = {
+        next: function next() {
+          var done = length <= i,
+              c = done ? '' : fromCodePoint(self.codePointAt(i));
+          i += c.length;
+          return done ? { done: done } : { done: done, value: c };
+        }
+      };
+      iterator[Si] = returnThis;
+      return iterator;
     };
-    iterator[Si] = returnThis;
-    return iterator;
+  })(Symbol.iterator, Array.prototype, String.prototype);
+}
+
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
+  Number.isNaN = Number.isNaN || function (value) {
+    return value !== value;
   };
-})(Symbol.iterator, Array.prototype, String.prototype);
 
-Number.isNaN = Number.isNaN || function (value) {
-  return value !== value;
-};
+  Number.isFinite = Number.isFinite || function (value) {
+    return typeof value === "number" && isFinite(value);
+  };
+}
 
-Number.isFinite = Number.isFinite || function (value) {
-  return typeof value === "number" && isFinite(value);
-};
 if (!String.prototype.endsWith || function () {
   try {
     return !"ab".endsWith("a", 1);
@@ -293,109 +300,112 @@ if (!String.prototype.startsWith || function () {
   };
 }
 
-if (!Array.from) {
-  Array.from = function () {
-    var toInteger = function toInteger(it) {
-      return isNaN(it = +it) ? 0 : (it > 0 ? Math.floor : Math.ceil)(it);
-    };
-    var toLength = function toLength(it) {
-      return it > 0 ? Math.min(toInteger(it), 0x1fffffffffffff) : 0;
-    };
-    var iterCall = function iterCall(iter, fn, val, index) {
-      try {
-        return fn(val, index);
-      } catch (E) {
-        if (typeof iter.return == 'function') iter.return();
-        throw E;
-      }
-    };
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-    return function from(arrayLike) {
-      var O = Object(arrayLike),
-          C = typeof this == 'function' ? this : Array,
-          aLen = arguments.length,
-          mapfn = aLen > 1 ? arguments[1] : undefined,
-          mapping = mapfn !== undefined,
-          index = 0,
-          iterFn = O[Symbol.iterator],
-          length,
-          result,
-          step,
-          iterator;
-      if (mapping) mapfn = mapfn.bind(aLen > 2 ? arguments[2] : undefined);
-      if (iterFn != undefined && !Array.isArray(arrayLike)) {
-        for (iterator = iterFn.call(O), result = new C(); !(step = iterator.next()).done; index++) {
-          result[index] = mapping ? iterCall(iterator, mapfn, step.value, index) : step.value;
+  if (!Array.from) {
+    Array.from = function () {
+      var toInteger = function toInteger(it) {
+        return isNaN(it = +it) ? 0 : (it > 0 ? Math.floor : Math.ceil)(it);
+      };
+      var toLength = function toLength(it) {
+        return it > 0 ? Math.min(toInteger(it), 0x1fffffffffffff) : 0;
+      };
+      var iterCall = function iterCall(iter, fn, val, index) {
+        try {
+          return fn(val, index);
+        } catch (E) {
+          if (typeof iter.return == 'function') iter.return();
+          throw E;
         }
-      } else {
-        length = toLength(O.length);
-        for (result = new C(length); length > index; index++) {
-          result[index] = mapping ? mapfn(O[index], index) : O[index];
+      };
+
+      return function from(arrayLike) {
+        var O = Object(arrayLike),
+            C = typeof this == 'function' ? this : Array,
+            aLen = arguments.length,
+            mapfn = aLen > 1 ? arguments[1] : undefined,
+            mapping = mapfn !== undefined,
+            index = 0,
+            iterFn = O[Symbol.iterator],
+            length,
+            result,
+            step,
+            iterator;
+        if (mapping) mapfn = mapfn.bind(aLen > 2 ? arguments[2] : undefined);
+        if (iterFn != undefined && !Array.isArray(arrayLike)) {
+          for (iterator = iterFn.call(O), result = new C(); !(step = iterator.next()).done; index++) {
+            result[index] = mapping ? iterCall(iterator, mapfn, step.value, index) : step.value;
+          }
+        } else {
+          length = toLength(O.length);
+          for (result = new C(length); length > index; index++) {
+            result[index] = mapping ? mapfn(O[index], index) : O[index];
+          }
         }
-      }
-      result.length = index;
-      return result;
-    };
-  }();
-}
+        result.length = index;
+        return result;
+      };
+    }();
+  }
 
-if (!Array.prototype.find) {
-  Object.defineProperty(Array.prototype, 'find', {
-    configurable: true,
-    writable: true,
-    enumerable: false,
-    value: function value(predicate) {
-      if (this === null) {
-        throw new TypeError('Array.prototype.find called on null or undefined');
-      }
-      if (typeof predicate !== 'function') {
-        throw new TypeError('predicate must be a function');
-      }
-      var list = Object(this);
-      var length = list.length >>> 0;
-      var thisArg = arguments[1];
-      var value;
-
-      for (var i = 0; i < length; i++) {
-        value = list[i];
-        if (predicate.call(thisArg, value, i, list)) {
-          return value;
+  if (!Array.prototype.find) {
+    Object.defineProperty(Array.prototype, 'find', {
+      configurable: true,
+      writable: true,
+      enumerable: false,
+      value: function value(predicate) {
+        if (this === null) {
+          throw new TypeError('Array.prototype.find called on null or undefined');
         }
+        if (typeof predicate !== 'function') {
+          throw new TypeError('predicate must be a function');
+        }
+        var list = Object(this);
+        var length = list.length >>> 0;
+        var thisArg = arguments[1];
+        var value;
+
+        for (var i = 0; i < length; i++) {
+          value = list[i];
+          if (predicate.call(thisArg, value, i, list)) {
+            return value;
+          }
+        }
+        return undefined;
       }
-      return undefined;
-    }
-  });
-}
+    });
+  }
 
-if (!Array.prototype.findIndex) {
-  Object.defineProperty(Array.prototype, 'findIndex', {
-    configurable: true,
-    writable: true,
-    enumerable: false,
-    value: function value(predicate) {
-      if (this === null) {
-        throw new TypeError('Array.prototype.findIndex called on null or undefined');
-      }
-      if (typeof predicate !== 'function') {
-        throw new TypeError('predicate must be a function');
-      }
-      var list = Object(this);
-      var length = list.length >>> 0;
-      var thisArg = arguments[1];
-      var value;
-
-      for (var i = 0; i < length; i++) {
-        value = list[i];
-        if (predicate.call(thisArg, value, i, list)) {
-          return i;
+  if (!Array.prototype.findIndex) {
+    Object.defineProperty(Array.prototype, 'findIndex', {
+      configurable: true,
+      writable: true,
+      enumerable: false,
+      value: function value(predicate) {
+        if (this === null) {
+          throw new TypeError('Array.prototype.findIndex called on null or undefined');
         }
+        if (typeof predicate !== 'function') {
+          throw new TypeError('predicate must be a function');
+        }
+        var list = Object(this);
+        var length = list.length >>> 0;
+        var thisArg = arguments[1];
+        var value;
+
+        for (var i = 0; i < length; i++) {
+          value = list[i];
+          if (predicate.call(thisArg, value, i, list)) {
+            return i;
+          }
+        }
+        return -1;
       }
-      return -1;
-    }
-  });
+    });
+  }
 }
 
-if (!Array.prototype.includes) {
+if (typeof FEATURE_NO_ES2016 === 'undefined' && !Array.prototype.includes) {
   Object.defineProperty(Array.prototype, 'includes', {
     configurable: true,
     writable: true,
@@ -429,375 +439,392 @@ if (!Array.prototype.includes) {
   });
 }
 
-(function () {
-  var needsFix = false;
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-  try {
-    var s = Object.keys('a');
-    needsFix = s.length !== 1 || s[0] !== '0';
-  } catch (e) {
-    needsFix = true;
-  }
+  (function () {
+    var needsFix = false;
 
-  if (needsFix) {
-    Object.keys = function () {
-      var hasOwnProperty = Object.prototype.hasOwnProperty,
-          hasDontEnumBug = !{ toString: null }.propertyIsEnumerable('toString'),
-          dontEnums = ['toString', 'toLocaleString', 'valueOf', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable', 'constructor'],
-          dontEnumsLength = dontEnums.length;
+    try {
+      var s = Object.keys('a');
+      needsFix = s.length !== 1 || s[0] !== '0';
+    } catch (e) {
+      needsFix = true;
+    }
 
-      return function (obj) {
-        if (obj === undefined || obj === null) {
-          throw TypeError('Cannot convert undefined or null to object');
-        }
+    if (needsFix) {
+      Object.keys = function () {
+        var hasOwnProperty = Object.prototype.hasOwnProperty,
+            hasDontEnumBug = !{ toString: null }.propertyIsEnumerable('toString'),
+            dontEnums = ['toString', 'toLocaleString', 'valueOf', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable', 'constructor'],
+            dontEnumsLength = dontEnums.length;
+
+        return function (obj) {
+          if (obj === undefined || obj === null) {
+            throw TypeError('Cannot convert undefined or null to object');
+          }
 
-        obj = Object(obj);
+          obj = Object(obj);
 
-        var result = [],
-            prop,
-            i;
+          var result = [],
+              prop,
+              i;
 
-        for (prop in obj) {
-          if (hasOwnProperty.call(obj, prop)) {
-            result.push(prop);
+          for (prop in obj) {
+            if (hasOwnProperty.call(obj, prop)) {
+              result.push(prop);
+            }
           }
-        }
 
-        if (hasDontEnumBug) {
-          for (i = 0; i < dontEnumsLength; i++) {
-            if (hasOwnProperty.call(obj, dontEnums[i])) {
-              result.push(dontEnums[i]);
+          if (hasDontEnumBug) {
+            for (i = 0; i < dontEnumsLength; i++) {
+              if (hasOwnProperty.call(obj, dontEnums[i])) {
+                result.push(dontEnums[i]);
+              }
             }
           }
-        }
 
-        return result;
-      };
-    }();
-  }
-})();
+          return result;
+        };
+      }();
+    }
+  })();
 
-(function (O) {
-  if ('assign' in O) {
-    return;
-  }
+  (function (O) {
+    if ('assign' in O) {
+      return;
+    }
 
-  O.defineProperty(O, 'assign', {
-    configurable: true,
-    writable: true,
-    value: function () {
-      var gOPS = O.getOwnPropertySymbols,
-          pIE = O.propertyIsEnumerable,
-          filterOS = gOPS ? function (self) {
-        return gOPS(self).filter(pIE, self);
-      } : function () {
-        return Array.prototype;
-      };
+    O.defineProperty(O, 'assign', {
+      configurable: true,
+      writable: true,
+      value: function () {
+        var gOPS = O.getOwnPropertySymbols,
+            pIE = O.propertyIsEnumerable,
+            filterOS = gOPS ? function (self) {
+          return gOPS(self).filter(pIE, self);
+        } : function () {
+          return Array.prototype;
+        };
+
+        return function assign(where) {
+          if (gOPS && !(where instanceof O)) {
+            console.warn('problematic Symbols', where);
+          }
 
-      return function assign(where) {
-        if (gOPS && !(where instanceof O)) {
-          console.warn('problematic Symbols', where);
-        }
+          function set(keyOrSymbol) {
+            where[keyOrSymbol] = arg[keyOrSymbol];
+          }
 
-        function set(keyOrSymbol) {
-          where[keyOrSymbol] = arg[keyOrSymbol];
-        }
+          for (var i = 1, ii = arguments.length; i < ii; ++i) {
+            var arg = arguments[i];
 
-        for (var i = 1, ii = arguments.length; i < ii; ++i) {
-          var arg = arguments[i];
+            if (arg === null || arg === undefined) {
+              continue;
+            }
 
-          if (arg === null || arg === undefined) {
-            continue;
+            O.keys(arg).concat(filterOS(arg)).forEach(set);
           }
 
-          O.keys(arg).concat(filterOS(arg)).forEach(set);
-        }
-
-        return where;
-      };
-    }()
-  });
-})(Object);
-
-(function (global) {
-  var i;
+          return where;
+        };
+      }()
+    });
+  })(Object);
+}
 
-  var defineProperty = Object.defineProperty,
-      is = function is(a, b) {
-    return a === b || a !== a && b !== b;
-  };
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-  if (typeof WeakMap == 'undefined') {
-    global.WeakMap = createCollection({
-      'delete': sharedDelete,
+  (function (global) {
+    var i;
 
-      clear: sharedClear,
+    var defineProperty = Object.defineProperty,
+        is = function is(a, b) {
+      return a === b || a !== a && b !== b;
+    };
 
-      get: sharedGet,
+    if (typeof WeakMap == 'undefined') {
+      global.WeakMap = createCollection({
+        'delete': sharedDelete,
 
-      has: mapHas,
+        clear: sharedClear,
 
-      set: sharedSet
-    }, true);
-  }
+        get: sharedGet,
 
-  if (typeof Map == 'undefined' || typeof new Map().values !== 'function' || !new Map().values().next) {
-    var _createCollection;
+        has: mapHas,
 
-    global.Map = createCollection((_createCollection = {
-      'delete': sharedDelete,
+        set: sharedSet
+      }, true);
+    }
 
-      has: mapHas,
+    if (typeof Map == 'undefined' || typeof new Map().values !== 'function' || !new Map().values().next) {
+      var _createCollection;
 
-      get: sharedGet,
+      global.Map = createCollection((_createCollection = {
+        'delete': sharedDelete,
 
-      set: sharedSet,
+        has: mapHas,
 
-      keys: sharedKeys,
+        get: sharedGet,
 
-      values: sharedValues,
+        set: sharedSet,
 
-      entries: mapEntries,
+        keys: sharedKeys,
 
-      forEach: sharedForEach,
+        values: sharedValues,
 
-      clear: sharedClear
-    }, _createCollection[Symbol.iterator] = mapEntries, _createCollection));
-  }
+        entries: mapEntries,
 
-  if (typeof Set == 'undefined' || typeof new Set().values !== 'function' || !new Set().values().next) {
-    var _createCollection2;
+        forEach: sharedForEach,
 
-    global.Set = createCollection((_createCollection2 = {
-      has: setHas,
+        clear: sharedClear
+      }, _createCollection[Symbol.iterator] = mapEntries, _createCollection));
+    }
 
-      add: sharedAdd,
+    if (typeof Set == 'undefined' || typeof new Set().values !== 'function' || !new Set().values().next) {
+      var _createCollection2;
 
-      'delete': sharedDelete,
+      global.Set = createCollection((_createCollection2 = {
+        has: setHas,
 
-      clear: sharedClear,
+        add: sharedAdd,
 
-      keys: sharedValues,
-      values: sharedValues,
+        'delete': sharedDelete,
 
-      entries: setEntries,
+        clear: sharedClear,
 
-      forEach: sharedForEach
-    }, _createCollection2[Symbol.iterator] = sharedValues, _createCollection2));
-  }
+        keys: sharedValues,
+        values: sharedValues,
 
-  if (typeof WeakSet == 'undefined') {
-    global.WeakSet = createCollection({
-      'delete': sharedDelete,
+        entries: setEntries,
 
-      add: sharedAdd,
+        forEach: sharedForEach
+      }, _createCollection2[Symbol.iterator] = sharedValues, _createCollection2));
+    }
 
-      clear: sharedClear,
+    if (typeof WeakSet == 'undefined') {
+      global.WeakSet = createCollection({
+        'delete': sharedDelete,
 
-      has: setHas
-    }, true);
-  }
+        add: sharedAdd,
 
-  function createCollection(proto, objectOnly) {
-    function Collection(a) {
-      if (!this || this.constructor !== Collection) return new Collection(a);
-      this._keys = [];
-      this._values = [];
-      this._itp = [];
-      this.objectOnly = objectOnly;
+        clear: sharedClear,
 
-      if (a) init.call(this, a);
+        has: setHas
+      }, true);
     }
 
-    if (!objectOnly) {
-      defineProperty(proto, 'size', {
-        get: sharedSize
-      });
-    }
+    function createCollection(proto, objectOnly) {
+      function Collection(a) {
+        if (!this || this.constructor !== Collection) return new Collection(a);
+        this._keys = [];
+        this._values = [];
+        this._itp = [];
+        this.objectOnly = objectOnly;
 
-    proto.constructor = Collection;
-    Collection.prototype = proto;
+        if (a) init.call(this, a);
+      }
 
-    return Collection;
-  }
+      if (!objectOnly) {
+        defineProperty(proto, 'size', {
+          get: sharedSize
+        });
+      }
 
-  function init(a) {
-    var i;
+      proto.constructor = Collection;
+      Collection.prototype = proto;
 
-    if (this.add) a.forEach(this.add, this);else a.forEach(function (a) {
-        this.set(a[0], a[1]);
-      }, this);
-  }
+      return Collection;
+    }
 
-  function sharedDelete(key) {
-    if (this.has(key)) {
-      this._keys.splice(i, 1);
-      this._values.splice(i, 1);
+    function init(a) {
+      var i;
 
-      this._itp.forEach(function (p) {
-        if (i < p[0]) p[0]--;
-      });
+      if (this.add) a.forEach(this.add, this);else a.forEach(function (a) {
+          this.set(a[0], a[1]);
+        }, this);
     }
 
-    return -1 < i;
-  };
-
-  function sharedGet(key) {
-    return this.has(key) ? this._values[i] : undefined;
-  }
+    function sharedDelete(key) {
+      if (this.has(key)) {
+        this._keys.splice(i, 1);
+        this._values.splice(i, 1);
 
-  function has(list, key) {
-    if (this.objectOnly && key !== Object(key)) throw new TypeError("Invalid value used as weak collection key");
+        this._itp.forEach(function (p) {
+          if (i < p[0]) p[0]--;
+        });
+      }
 
-    if (key != key || key === 0) for (i = list.length; i-- && !is(list[i], key);) {} else i = list.indexOf(key);
-    return -1 < i;
-  }
+      return -1 < i;
+    };
 
-  function setHas(value) {
-    return has.call(this, this._values, value);
-  }
+    function sharedGet(key) {
+      return this.has(key) ? this._values[i] : undefined;
+    }
 
-  function mapHas(value) {
-    return has.call(this, this._keys, value);
-  }
+    function has(list, key) {
+      if (this.objectOnly && key !== Object(key)) throw new TypeError("Invalid value used as weak collection key");
 
-  function sharedSet(key, value) {
-    this.has(key) ? this._values[i] = value : this._values[this._keys.push(key) - 1] = value;
-    return this;
-  }
+      if (key != key || key === 0) for (i = list.length; i-- && !is(list[i], key);) {} else i = list.indexOf(key);
+      return -1 < i;
+    }
 
-  function sharedAdd(value) {
-    if (!this.has(value)) this._values.push(value);
-    return this;
-  }
+    function setHas(value) {
+      return has.call(this, this._values, value);
+    }
 
-  function sharedClear() {
-    (this._keys || 0).length = this._values.length = 0;
-  }
+    function mapHas(value) {
+      return has.call(this, this._keys, value);
+    }
 
-  function sharedKeys() {
-    return sharedIterator(this._itp, this._keys);
-  }
+    function sharedSet(key, value) {
+      this.has(key) ? this._values[i] = value : this._values[this._keys.push(key) - 1] = value;
+      return this;
+    }
 
-  function sharedValues() {
-    return sharedIterator(this._itp, this._values);
-  }
+    function sharedAdd(value) {
+      if (!this.has(value)) this._values.push(value);
+      return this;
+    }
 
-  function mapEntries() {
-    return sharedIterator(this._itp, this._keys, this._values);
-  }
+    function sharedClear() {
+      (this._keys || 0).length = this._values.length = 0;
+    }
 
-  function setEntries() {
-    return sharedIterator(this._itp, this._values, this._values);
-  }
+    function sharedKeys() {
+      return sharedIterator(this._itp, this._keys);
+    }
 
-  function sharedIterator(itp, array, array2) {
-    var _ref;
+    function sharedValues() {
+      return sharedIterator(this._itp, this._values);
+    }
 
-    var p = [0],
-        done = false;
-    itp.push(p);
-    return _ref = {}, _ref[Symbol.iterator] = function () {
-      return this;
-    }, _ref.next = function next() {
-      var v,
-          k = p[0];
-      if (!done && k < array.length) {
-        v = array2 ? [array[k], array2[k]] : array[k];
-        p[0]++;
-      } else {
-        done = true;
-        itp.splice(itp.indexOf(p), 1);
-      }
-      return { done: done, value: v };
-    }, _ref;
-  }
+    function mapEntries() {
+      return sharedIterator(this._itp, this._keys, this._values);
+    }
 
-  function sharedSize() {
-    return this._values.length;
-  }
+    function setEntries() {
+      return sharedIterator(this._itp, this._values, this._values);
+    }
 
-  function sharedForEach(callback, context) {
-    var it = this.entries();
-    for (;;) {
-      var r = it.next();
-      if (r.done) break;
-      callback.call(context, r.value[1], r.value[0], this);
+    function sharedIterator(itp, array, array2) {
+      var _ref;
+
+      var p = [0],
+          done = false;
+      itp.push(p);
+      return _ref = {}, _ref[Symbol.iterator] = function () {
+        return this;
+      }, _ref.next = function next() {
+        var v,
+            k = p[0];
+        if (!done && k < array.length) {
+          v = array2 ? [array[k], array2[k]] : array[k];
+          p[0]++;
+        } else {
+          done = true;
+          itp.splice(itp.indexOf(p), 1);
+        }
+        return { done: done, value: v };
+      }, _ref;
     }
-  }
-})(PLATFORM.global);
 
-var emptyMetadata = Object.freeze({});
-var metadataContainerKey = '__metadata__';
-var bind = Function.prototype.bind;
+    function sharedSize() {
+      return this._values.length;
+    }
 
-if (typeof PLATFORM.global.Reflect === 'undefined') {
-  PLATFORM.global.Reflect = {};
+    function sharedForEach(callback, context) {
+      var it = this.entries();
+      for (;;) {
+        var r = it.next();
+        if (r.done) break;
+        callback.call(context, r.value[1], r.value[0], this);
+      }
+    }
+  })(PLATFORM.global);
 }
 
-if (typeof Reflect.getOwnMetadata !== 'function') {
-  Reflect.getOwnMetadata = function (metadataKey, target, targetKey) {
-    if (target.hasOwnProperty(metadataContainerKey)) {
-      return (target[metadataContainerKey][targetKey] || emptyMetadata)[metadataKey];
+if (typeof FEATURE_NO_ES2015 === 'undefined') {
+  (function () {
+
+    var bind = Function.prototype.bind;
+
+    if (typeof PLATFORM.global.Reflect === 'undefined') {
+      PLATFORM.global.Reflect = {};
     }
-  };
-}
 
-if (typeof Reflect.defineMetadata !== 'function') {
-  Reflect.defineMetadata = function (metadataKey, metadataValue, target, targetKey) {
-    var metadataContainer = target.hasOwnProperty(metadataContainerKey) ? target[metadataContainerKey] : target[metadataContainerKey] = {};
-    var targetContainer = metadataContainer[targetKey] || (metadataContainer[targetKey] = {});
-    targetContainer[metadataKey] = metadataValue;
-  };
-}
+    if (typeof Reflect.defineProperty !== 'function') {
+      Reflect.defineProperty = function (target, propertyKey, descriptor) {
+        if ((typeof target === 'undefined' ? 'undefined' : _typeof(target)) === 'object' ? target === null : typeof target !== 'function') {
+          throw new TypeError('Reflect.defineProperty called on non-object');
+        }
+        try {
+          Object.defineProperty(target, propertyKey, descriptor);
+          return true;
+        } catch (e) {
+          return false;
+        }
+      };
+    }
 
-if (typeof Reflect.metadata !== 'function') {
-  Reflect.metadata = function (metadataKey, metadataValue) {
-    return function (target, targetKey) {
-      Reflect.defineMetadata(metadataKey, metadataValue, target, targetKey);
-    };
-  };
-}
+    if (typeof Reflect.construct !== 'function') {
+      Reflect.construct = function (Target, args) {
+        if (args) {
+          switch (args.length) {
+            case 0:
+              return new Target();
+            case 1:
+              return new Target(args[0]);
+            case 2:
+              return new Target(args[0], args[1]);
+            case 3:
+              return new Target(args[0], args[1], args[2]);
+            case 4:
+              return new Target(args[0], args[1], args[2], args[3]);
+          }
+        }
 
-if (typeof Reflect.defineProperty !== 'function') {
-  Reflect.defineProperty = function (target, propertyKey, descriptor) {
-    if ((typeof target === 'undefined' ? 'undefined' : _typeof(target)) === 'object' ? target === null : typeof target !== 'function') {
-      throw new TypeError('Reflect.defineProperty called on non-object');
+        var a = [null];
+        a.push.apply(a, args);
+        return new (bind.apply(Target, a))();
+      };
     }
-    try {
-      Object.defineProperty(target, propertyKey, descriptor);
-      return true;
-    } catch (e) {
-      return false;
+
+    if (typeof Reflect.ownKeys !== 'function') {
+      Reflect.ownKeys = function (o) {
+        return Object.getOwnPropertyNames(o).concat(Object.getOwnPropertySymbols(o));
+      };
     }
-  };
+  })();
 }
 
-if (typeof Reflect.construct !== 'function') {
-  Reflect.construct = function (Target, args) {
-    if (args) {
-      switch (args.length) {
-        case 0:
-          return new Target();
-        case 1:
-          return new Target(args[0]);
-        case 2:
-          return new Target(args[0], args[1]);
-        case 3:
-          return new Target(args[0], args[1], args[2]);
-        case 4:
-          return new Target(args[0], args[1], args[2], args[3]);
-      }
+if (typeof FEATURE_NO_ESNEXT === 'undefined') {
+  (function () {
+
+    var emptyMetadata = Object.freeze({});
+    var metadataContainerKey = '__metadata__';
+
+    if (typeof Reflect.getOwnMetadata !== 'function') {
+      Reflect.getOwnMetadata = function (metadataKey, target, targetKey) {
+        if (target.hasOwnProperty(metadataContainerKey)) {
+          return (target[metadataContainerKey][targetKey] || emptyMetadata)[metadataKey];
+        }
+      };
     }
 
-    var a = [null];
-    a.push.apply(a, args);
-    return new (bind.apply(Target, a))();
-  };
-}
+    if (typeof Reflect.defineMetadata !== 'function') {
+      Reflect.defineMetadata = function (metadataKey, metadataValue, target, targetKey) {
+        var metadataContainer = target.hasOwnProperty(metadataContainerKey) ? target[metadataContainerKey] : target[metadataContainerKey] = {};
+        var targetContainer = metadataContainer[targetKey] || (metadataContainer[targetKey] = {});
+        targetContainer[metadataKey] = metadataValue;
+      };
+    }
 
-if (typeof Reflect.ownKeys !== 'function') {
-  Reflect.ownKeys = function (o) {
-    return Object.getOwnPropertyNames(o).concat(Object.getOwnPropertySymbols(o));
-  };
+    if (typeof Reflect.metadata !== 'function') {
+      Reflect.metadata = function (metadataKey, metadataValue) {
+        return function (target, targetKey) {
+          Reflect.defineMetadata(metadataKey, metadataValue, target, targetKey);
+        };
+      };
+    }
+  })();
 }
\ No newline at end of file
diff --git a/dist/system/aurelia-polyfills.js b/dist/system/aurelia-polyfills.js
index c42b63c..e8b0907 100644
--- a/dist/system/aurelia-polyfills.js
+++ b/dist/system/aurelia-polyfills.js
@@ -3,7 +3,7 @@
 System.register(['aurelia-pal'], function (_export, _context) {
   "use strict";
 
-  var PLATFORM, _typeof, emptyMetadata, metadataContainerKey, bind;
+  var PLATFORM, _typeof;
 
   return {
     setters: [function (_aureliaPal) {
@@ -17,266 +17,273 @@ System.register(['aurelia-pal'], function (_export, _context) {
       };
 
 
-      (function (Object, GOPS) {
-        'use strict';
-
-        if (GOPS in Object) return;
-
-        var setDescriptor,
-            G = PLATFORM.global,
-            id = 0,
-            random = '' + Math.random(),
-            prefix = '__\x01symbol:',
-            prefixLength = prefix.length,
-            internalSymbol = '__\x01symbol@@' + random,
-            DP = 'defineProperty',
-            DPies = 'defineProperties',
-            GOPN = 'getOwnPropertyNames',
-            GOPD = 'getOwnPropertyDescriptor',
-            PIE = 'propertyIsEnumerable',
-            gOPN = Object[GOPN],
-            gOPD = Object[GOPD],
-            create = Object.create,
-            keys = Object.keys,
-            defineProperty = Object[DP],
-            $defineProperties = Object[DPies],
-            descriptor = gOPD(Object, GOPN),
-            ObjectProto = Object.prototype,
-            hOP = ObjectProto.hasOwnProperty,
-            pIE = ObjectProto[PIE],
-            toString = ObjectProto.toString,
-            indexOf = Array.prototype.indexOf || function (v) {
-          for (var i = this.length; i-- && this[i] !== v;) {}
-          return i;
-        },
-            addInternalIfNeeded = function addInternalIfNeeded(o, uid, enumerable) {
-          if (!hOP.call(o, internalSymbol)) {
-            defineProperty(o, internalSymbol, {
-              enumerable: false,
-              configurable: false,
-              writable: false,
-              value: {}
-            });
-          }
-          o[internalSymbol]['@@' + uid] = enumerable;
-        },
-            createWithSymbols = function createWithSymbols(proto, descriptors) {
-          var self = create(proto);
-          gOPN(descriptors).forEach(function (key) {
-            if (propertyIsEnumerable.call(descriptors, key)) {
-              $defineProperty(self, key, descriptors[key]);
-            }
-          });
-          return self;
-        },
-            copyAsNonEnumerable = function copyAsNonEnumerable(descriptor) {
-          var newDescriptor = create(descriptor);
-          newDescriptor.enumerable = false;
-          return newDescriptor;
-        },
-            get = function get() {},
-            onlyNonSymbols = function onlyNonSymbols(name) {
-          return name != internalSymbol && !hOP.call(source, name);
-        },
-            onlySymbols = function onlySymbols(name) {
-          return name != internalSymbol && hOP.call(source, name);
-        },
-            propertyIsEnumerable = function propertyIsEnumerable(key) {
-          var uid = '' + key;
-          return onlySymbols(uid) ? hOP.call(this, uid) && this[internalSymbol]['@@' + uid] : pIE.call(this, key);
-        },
-            setAndGetSymbol = function setAndGetSymbol(uid) {
-          var descriptor = {
-            enumerable: false,
-            configurable: true,
-            get: get,
-            set: function set(value) {
-              setDescriptor(this, uid, {
+      if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
+        (function (Object, GOPS) {
+          'use strict';
+
+          if (GOPS in Object) return;
+
+          var setDescriptor,
+              G = PLATFORM.global,
+              id = 0,
+              random = '' + Math.random(),
+              prefix = '__\x01symbol:',
+              prefixLength = prefix.length,
+              internalSymbol = '__\x01symbol@@' + random,
+              DP = 'defineProperty',
+              DPies = 'defineProperties',
+              GOPN = 'getOwnPropertyNames',
+              GOPD = 'getOwnPropertyDescriptor',
+              PIE = 'propertyIsEnumerable',
+              gOPN = Object[GOPN],
+              gOPD = Object[GOPD],
+              create = Object.create,
+              keys = Object.keys,
+              defineProperty = Object[DP],
+              $defineProperties = Object[DPies],
+              descriptor = gOPD(Object, GOPN),
+              ObjectProto = Object.prototype,
+              hOP = ObjectProto.hasOwnProperty,
+              pIE = ObjectProto[PIE],
+              toString = ObjectProto.toString,
+              indexOf = Array.prototype.indexOf || function (v) {
+            for (var i = this.length; i-- && this[i] !== v;) {}
+            return i;
+          },
+              addInternalIfNeeded = function addInternalIfNeeded(o, uid, enumerable) {
+            if (!hOP.call(o, internalSymbol)) {
+              defineProperty(o, internalSymbol, {
                 enumerable: false,
-                configurable: true,
-                writable: true,
-                value: value
+                configurable: false,
+                writable: false,
+                value: {}
               });
-              addInternalIfNeeded(this, uid, true);
             }
-          };
-          defineProperty(ObjectProto, uid, descriptor);
-          return source[uid] = defineProperty(Object(uid), 'constructor', sourceConstructor);
-        },
-            _Symbol = function _Symbol2(description) {
-          if (this && this !== G) {
-            throw new TypeError('Symbol is not a constructor');
-          }
-          return setAndGetSymbol(prefix.concat(description || '', random, ++id));
-        },
-            source = create(null),
-            sourceConstructor = { value: _Symbol },
-            sourceMap = function sourceMap(uid) {
-          return source[uid];
-        },
-            $defineProperty = function defineProp(o, key, descriptor) {
-          var uid = '' + key;
-          if (onlySymbols(uid)) {
-            setDescriptor(o, uid, descriptor.enumerable ? copyAsNonEnumerable(descriptor) : descriptor);
-            addInternalIfNeeded(o, uid, !!descriptor.enumerable);
-          } else {
-            defineProperty(o, key, descriptor);
-          }
-          return o;
-        },
-            $getOwnPropertySymbols = function getOwnPropertySymbols(o) {
-          var cof = toString.call(o);
-          o = cof === '[object String]' ? o.split('') : Object(o);
-          return gOPN(o).filter(onlySymbols).map(sourceMap);
-        };
-
-        descriptor.value = $defineProperty;
-        defineProperty(Object, DP, descriptor);
-
-        descriptor.value = $getOwnPropertySymbols;
-        defineProperty(Object, GOPS, descriptor);
-
-        descriptor.value = function getOwnPropertyNames(o) {
-          return gOPN(o).filter(onlyNonSymbols);
-        };
-        defineProperty(Object, GOPN, descriptor);
-
-        descriptor.value = function defineProperties(o, descriptors) {
-          var symbols = $getOwnPropertySymbols(descriptors);
-          if (symbols.length) {
-            keys(descriptors).concat(symbols).forEach(function (uid) {
-              if (propertyIsEnumerable.call(descriptors, uid)) {
-                $defineProperty(o, uid, descriptors[uid]);
+            o[internalSymbol]['@@' + uid] = enumerable;
+          },
+              createWithSymbols = function createWithSymbols(proto, descriptors) {
+            var self = create(proto);
+            gOPN(descriptors).forEach(function (key) {
+              if (propertyIsEnumerable.call(descriptors, key)) {
+                $defineProperty(self, key, descriptors[key]);
               }
             });
-          } else {
-            $defineProperties(o, descriptors);
-          }
-          return o;
-        };
-        defineProperty(Object, DPies, descriptor);
+            return self;
+          },
+              copyAsNonEnumerable = function copyAsNonEnumerable(descriptor) {
+            var newDescriptor = create(descriptor);
+            newDescriptor.enumerable = false;
+            return newDescriptor;
+          },
+              get = function get() {},
+              onlyNonSymbols = function onlyNonSymbols(name) {
+            return name != internalSymbol && !hOP.call(source, name);
+          },
+              onlySymbols = function onlySymbols(name) {
+            return name != internalSymbol && hOP.call(source, name);
+          },
+              propertyIsEnumerable = function propertyIsEnumerable(key) {
+            var uid = '' + key;
+            return onlySymbols(uid) ? hOP.call(this, uid) && this[internalSymbol]['@@' + uid] : pIE.call(this, key);
+          },
+              setAndGetSymbol = function setAndGetSymbol(uid) {
+            var descriptor = {
+              enumerable: false,
+              configurable: true,
+              get: get,
+              set: function set(value) {
+                setDescriptor(this, uid, {
+                  enumerable: false,
+                  configurable: true,
+                  writable: true,
+                  value: value
+                });
+                addInternalIfNeeded(this, uid, true);
+              }
+            };
+            defineProperty(ObjectProto, uid, descriptor);
+            return source[uid] = defineProperty(Object(uid), 'constructor', sourceConstructor);
+          },
+              _Symbol = function _Symbol2(description) {
+            if (this && this !== G) {
+              throw new TypeError('Symbol is not a constructor');
+            }
+            return setAndGetSymbol(prefix.concat(description || '', random, ++id));
+          },
+              source = create(null),
+              sourceConstructor = { value: _Symbol },
+              sourceMap = function sourceMap(uid) {
+            return source[uid];
+          },
+              $defineProperty = function defineProp(o, key, descriptor) {
+            var uid = '' + key;
+            if (onlySymbols(uid)) {
+              setDescriptor(o, uid, descriptor.enumerable ? copyAsNonEnumerable(descriptor) : descriptor);
+              addInternalIfNeeded(o, uid, !!descriptor.enumerable);
+            } else {
+              defineProperty(o, key, descriptor);
+            }
+            return o;
+          },
+              $getOwnPropertySymbols = function getOwnPropertySymbols(o) {
+            var cof = toString.call(o);
+            o = cof === '[object String]' ? o.split('') : Object(o);
+            return gOPN(o).filter(onlySymbols).map(sourceMap);
+          };
 
-        descriptor.value = propertyIsEnumerable;
-        defineProperty(ObjectProto, PIE, descriptor);
+          descriptor.value = $defineProperty;
+          defineProperty(Object, DP, descriptor);
 
-        descriptor.value = _Symbol;
-        defineProperty(G, 'Symbol', descriptor);
+          descriptor.value = $getOwnPropertySymbols;
+          defineProperty(Object, GOPS, descriptor);
 
-        descriptor.value = function (key) {
-          var uid = prefix.concat(prefix, key, random);
-          return uid in ObjectProto ? source[uid] : setAndGetSymbol(uid);
-        };
-        defineProperty(_Symbol, 'for', descriptor);
+          descriptor.value = function getOwnPropertyNames(o) {
+            return gOPN(o).filter(onlyNonSymbols);
+          };
+          defineProperty(Object, GOPN, descriptor);
+
+          descriptor.value = function defineProperties(o, descriptors) {
+            var symbols = $getOwnPropertySymbols(descriptors);
+            if (symbols.length) {
+              keys(descriptors).concat(symbols).forEach(function (uid) {
+                if (propertyIsEnumerable.call(descriptors, uid)) {
+                  $defineProperty(o, uid, descriptors[uid]);
+                }
+              });
+            } else {
+              $defineProperties(o, descriptors);
+            }
+            return o;
+          };
+          defineProperty(Object, DPies, descriptor);
 
-        descriptor.value = function (symbol) {
-          return hOP.call(source, symbol) ? symbol.slice(prefixLength * 2, -random.length) : void 0;
-        };
-        defineProperty(_Symbol, 'keyFor', descriptor);
+          descriptor.value = propertyIsEnumerable;
+          defineProperty(ObjectProto, PIE, descriptor);
 
-        descriptor.value = function getOwnPropertyDescriptor(o, key) {
-          var descriptor = gOPD(o, key);
-          if (descriptor && onlySymbols(key)) {
-            descriptor.enumerable = propertyIsEnumerable.call(o, key);
-          }
-          return descriptor;
-        };
-        defineProperty(Object, GOPD, descriptor);
+          descriptor.value = _Symbol;
+          defineProperty(G, 'Symbol', descriptor);
 
-        descriptor.value = function (proto, descriptors) {
-          return arguments.length === 1 ? create(proto) : createWithSymbols(proto, descriptors);
-        };
-        defineProperty(Object, 'create', descriptor);
+          descriptor.value = function (key) {
+            var uid = prefix.concat(prefix, key, random);
+            return uid in ObjectProto ? source[uid] : setAndGetSymbol(uid);
+          };
+          defineProperty(_Symbol, 'for', descriptor);
 
-        descriptor.value = function () {
-          var str = toString.call(this);
-          return str === '[object String]' && onlySymbols(this) ? '[object Symbol]' : str;
-        };
-        defineProperty(ObjectProto, 'toString', descriptor);
+          descriptor.value = function (symbol) {
+            return hOP.call(source, symbol) ? symbol.slice(prefixLength * 2, -random.length) : void 0;
+          };
+          defineProperty(_Symbol, 'keyFor', descriptor);
 
-        try {
-          setDescriptor = create(defineProperty({}, prefix, {
-            get: function get() {
-              return defineProperty(this, prefix, { value: false })[prefix];
+          descriptor.value = function getOwnPropertyDescriptor(o, key) {
+            var descriptor = gOPD(o, key);
+            if (descriptor && onlySymbols(key)) {
+              descriptor.enumerable = propertyIsEnumerable.call(o, key);
             }
-          }))[prefix] || defineProperty;
-        } catch (o_O) {
-          setDescriptor = function setDescriptor(o, key, descriptor) {
-            var protoDescriptor = gOPD(ObjectProto, key);
-            delete ObjectProto[key];
-            defineProperty(o, key, descriptor);
-            defineProperty(ObjectProto, key, protoDescriptor);
+            return descriptor;
           };
-        }
-      })(Object, 'getOwnPropertySymbols');
-
-      (function (O, S) {
-        var dP = O.defineProperty,
-            ObjectProto = O.prototype,
-            toString = ObjectProto.toString,
-            toStringTag = 'toStringTag',
-            descriptor;
-        ['iterator', 'match', 'replace', 'search', 'split', 'hasInstance', 'isConcatSpreadable', 'unscopables', 'species', 'toPrimitive', toStringTag].forEach(function (name) {
-          if (!(name in Symbol)) {
-            dP(Symbol, name, { value: Symbol(name) });
-            switch (name) {
-              case toStringTag:
-                descriptor = O.getOwnPropertyDescriptor(ObjectProto, 'toString');
-                descriptor.value = function () {
-                  var str = toString.call(this),
-                      tst = typeof this === 'undefined' || this === null ? undefined : this[Symbol.toStringTag];
-                  return typeof tst === 'undefined' ? str : '[object ' + tst + ']';
-                };
-                dP(ObjectProto, 'toString', descriptor);
-                break;
-            }
-          }
-        });
-      })(Object, Symbol);
+          defineProperty(Object, GOPD, descriptor);
 
-      (function (Si, AP, SP) {
+          descriptor.value = function (proto, descriptors) {
+            return arguments.length === 1 ? create(proto) : createWithSymbols(proto, descriptors);
+          };
+          defineProperty(Object, 'create', descriptor);
 
-        function returnThis() {
-          return this;
-        }
+          descriptor.value = function () {
+            var str = toString.call(this);
+            return str === '[object String]' && onlySymbols(this) ? '[object Symbol]' : str;
+          };
+          defineProperty(ObjectProto, 'toString', descriptor);
 
-        if (!AP[Si]) AP[Si] = function () {
-          var i = 0,
-              self = this,
-              iterator = {
-            next: function next() {
-              var done = self.length <= i;
-              return done ? { done: done } : { done: done, value: self[i++] };
+          try {
+            setDescriptor = create(defineProperty({}, prefix, {
+              get: function get() {
+                return defineProperty(this, prefix, { value: false })[prefix];
+              }
+            }))[prefix] || defineProperty;
+          } catch (o_O) {
+            setDescriptor = function setDescriptor(o, key, descriptor) {
+              var protoDescriptor = gOPD(ObjectProto, key);
+              delete ObjectProto[key];
+              defineProperty(o, key, descriptor);
+              defineProperty(ObjectProto, key, protoDescriptor);
+            };
+          }
+        })(Object, 'getOwnPropertySymbols');
+
+        (function (O, S) {
+          var dP = O.defineProperty,
+              ObjectProto = O.prototype,
+              toString = ObjectProto.toString,
+              toStringTag = 'toStringTag',
+              descriptor;
+          ['iterator', 'match', 'replace', 'search', 'split', 'hasInstance', 'isConcatSpreadable', 'unscopables', 'species', 'toPrimitive', toStringTag].forEach(function (name) {
+            if (!(name in Symbol)) {
+              dP(Symbol, name, { value: Symbol(name) });
+              switch (name) {
+                case toStringTag:
+                  descriptor = O.getOwnPropertyDescriptor(ObjectProto, 'toString');
+                  descriptor.value = function () {
+                    var str = toString.call(this),
+                        tst = typeof this === 'undefined' || this === null ? undefined : this[Symbol.toStringTag];
+                    return typeof tst === 'undefined' ? str : '[object ' + tst + ']';
+                  };
+                  dP(ObjectProto, 'toString', descriptor);
+                  break;
+              }
             }
+          });
+        })(Object, Symbol);
+
+        (function (Si, AP, SP) {
+
+          function returnThis() {
+            return this;
+          }
+
+          if (!AP[Si]) AP[Si] = function () {
+            var i = 0,
+                self = this,
+                iterator = {
+              next: function next() {
+                var done = self.length <= i;
+                return done ? { done: done } : { done: done, value: self[i++] };
+              }
+            };
+            iterator[Si] = returnThis;
+            return iterator;
           };
-          iterator[Si] = returnThis;
-          return iterator;
-        };
 
-        if (!SP[Si]) SP[Si] = function () {
-          var fromCodePoint = String.fromCodePoint,
-              self = this,
-              i = 0,
-              length = self.length,
-              iterator = {
-            next: function next() {
-              var done = length <= i,
-                  c = done ? '' : fromCodePoint(self.codePointAt(i));
-              i += c.length;
-              return done ? { done: done } : { done: done, value: c };
-            }
+          if (!SP[Si]) SP[Si] = function () {
+            var fromCodePoint = String.fromCodePoint,
+                self = this,
+                i = 0,
+                length = self.length,
+                iterator = {
+              next: function next() {
+                var done = length <= i,
+                    c = done ? '' : fromCodePoint(self.codePointAt(i));
+                i += c.length;
+                return done ? { done: done } : { done: done, value: c };
+              }
+            };
+            iterator[Si] = returnThis;
+            return iterator;
           };
-          iterator[Si] = returnThis;
-          return iterator;
+        })(Symbol.iterator, Array.prototype, String.prototype);
+      }
+
+      if (typeof FEATURE_NO_ES2015 === 'undefined') {
+
+        Number.isNaN = Number.isNaN || function (value) {
+          return value !== value;
         };
-      })(Symbol.iterator, Array.prototype, String.prototype);
 
-      Number.isNaN = Number.isNaN || function (value) {
-        return value !== value;
-      };
+        Number.isFinite = Number.isFinite || function (value) {
+          return typeof value === "number" && isFinite(value);
+        };
+      }
 
-      Number.isFinite = Number.isFinite || function (value) {
-        return typeof value === "number" && isFinite(value);
-      };
       if (!String.prototype.endsWith || function () {
         try {
           return !"ab".endsWith("a", 1);
@@ -308,109 +315,112 @@ System.register(['aurelia-pal'], function (_export, _context) {
         };
       }
 
-      if (!Array.from) {
-        Array.from = function () {
-          var toInteger = function toInteger(it) {
-            return isNaN(it = +it) ? 0 : (it > 0 ? Math.floor : Math.ceil)(it);
-          };
-          var toLength = function toLength(it) {
-            return it > 0 ? Math.min(toInteger(it), 0x1fffffffffffff) : 0;
-          };
-          var iterCall = function iterCall(iter, fn, val, index) {
-            try {
-              return fn(val, index);
-            } catch (E) {
-              if (typeof iter.return == 'function') iter.return();
-              throw E;
-            }
-          };
+      if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-          return function from(arrayLike) {
-            var O = Object(arrayLike),
-                C = typeof this == 'function' ? this : Array,
-                aLen = arguments.length,
-                mapfn = aLen > 1 ? arguments[1] : undefined,
-                mapping = mapfn !== undefined,
-                index = 0,
-                iterFn = O[Symbol.iterator],
-                length,
-                result,
-                step,
-                iterator;
-            if (mapping) mapfn = mapfn.bind(aLen > 2 ? arguments[2] : undefined);
-            if (iterFn != undefined && !Array.isArray(arrayLike)) {
-              for (iterator = iterFn.call(O), result = new C(); !(step = iterator.next()).done; index++) {
-                result[index] = mapping ? iterCall(iterator, mapfn, step.value, index) : step.value;
+        if (!Array.from) {
+          Array.from = function () {
+            var toInteger = function toInteger(it) {
+              return isNaN(it = +it) ? 0 : (it > 0 ? Math.floor : Math.ceil)(it);
+            };
+            var toLength = function toLength(it) {
+              return it > 0 ? Math.min(toInteger(it), 0x1fffffffffffff) : 0;
+            };
+            var iterCall = function iterCall(iter, fn, val, index) {
+              try {
+                return fn(val, index);
+              } catch (E) {
+                if (typeof iter.return == 'function') iter.return();
+                throw E;
               }
-            } else {
-              length = toLength(O.length);
-              for (result = new C(length); length > index; index++) {
-                result[index] = mapping ? mapfn(O[index], index) : O[index];
+            };
+
+            return function from(arrayLike) {
+              var O = Object(arrayLike),
+                  C = typeof this == 'function' ? this : Array,
+                  aLen = arguments.length,
+                  mapfn = aLen > 1 ? arguments[1] : undefined,
+                  mapping = mapfn !== undefined,
+                  index = 0,
+                  iterFn = O[Symbol.iterator],
+                  length,
+                  result,
+                  step,
+                  iterator;
+              if (mapping) mapfn = mapfn.bind(aLen > 2 ? arguments[2] : undefined);
+              if (iterFn != undefined && !Array.isArray(arrayLike)) {
+                for (iterator = iterFn.call(O), result = new C(); !(step = iterator.next()).done; index++) {
+                  result[index] = mapping ? iterCall(iterator, mapfn, step.value, index) : step.value;
+                }
+              } else {
+                length = toLength(O.length);
+                for (result = new C(length); length > index; index++) {
+                  result[index] = mapping ? mapfn(O[index], index) : O[index];
+                }
               }
-            }
-            result.length = index;
-            return result;
-          };
-        }();
-      }
+              result.length = index;
+              return result;
+            };
+          }();
+        }
 
-      if (!Array.prototype.find) {
-        Object.defineProperty(Array.prototype, 'find', {
-          configurable: true,
-          writable: true,
-          enumerable: false,
-          value: function value(predicate) {
-            if (this === null) {
-              throw new TypeError('Array.prototype.find called on null or undefined');
-            }
-            if (typeof predicate !== 'function') {
-              throw new TypeError('predicate must be a function');
-            }
-            var list = Object(this);
-            var length = list.length >>> 0;
-            var thisArg = arguments[1];
-            var value;
-
-            for (var i = 0; i < length; i++) {
-              value = list[i];
-              if (predicate.call(thisArg, value, i, list)) {
-                return value;
+        if (!Array.prototype.find) {
+          Object.defineProperty(Array.prototype, 'find', {
+            configurable: true,
+            writable: true,
+            enumerable: false,
+            value: function value(predicate) {
+              if (this === null) {
+                throw new TypeError('Array.prototype.find called on null or undefined');
+              }
+              if (typeof predicate !== 'function') {
+                throw new TypeError('predicate must be a function');
+              }
+              var list = Object(this);
+              var length = list.length >>> 0;
+              var thisArg = arguments[1];
+              var value;
+
+              for (var i = 0; i < length; i++) {
+                value = list[i];
+                if (predicate.call(thisArg, value, i, list)) {
+                  return value;
+                }
               }
+              return undefined;
             }
-            return undefined;
-          }
-        });
-      }
+          });
+        }
 
-      if (!Array.prototype.findIndex) {
-        Object.defineProperty(Array.prototype, 'findIndex', {
-          configurable: true,
-          writable: true,
-          enumerable: false,
-          value: function value(predicate) {
-            if (this === null) {
-              throw new TypeError('Array.prototype.findIndex called on null or undefined');
-            }
-            if (typeof predicate !== 'function') {
-              throw new TypeError('predicate must be a function');
-            }
-            var list = Object(this);
-            var length = list.length >>> 0;
-            var thisArg = arguments[1];
-            var value;
-
-            for (var i = 0; i < length; i++) {
-              value = list[i];
-              if (predicate.call(thisArg, value, i, list)) {
-                return i;
+        if (!Array.prototype.findIndex) {
+          Object.defineProperty(Array.prototype, 'findIndex', {
+            configurable: true,
+            writable: true,
+            enumerable: false,
+            value: function value(predicate) {
+              if (this === null) {
+                throw new TypeError('Array.prototype.findIndex called on null or undefined');
+              }
+              if (typeof predicate !== 'function') {
+                throw new TypeError('predicate must be a function');
+              }
+              var list = Object(this);
+              var length = list.length >>> 0;
+              var thisArg = arguments[1];
+              var value;
+
+              for (var i = 0; i < length; i++) {
+                value = list[i];
+                if (predicate.call(thisArg, value, i, list)) {
+                  return i;
+                }
               }
+              return -1;
             }
-            return -1;
-          }
-        });
+          });
+        }
       }
 
-      if (!Array.prototype.includes) {
+      if (typeof FEATURE_NO_ES2016 === 'undefined' && !Array.prototype.includes) {
         Object.defineProperty(Array.prototype, 'includes', {
           configurable: true,
           writable: true,
@@ -444,378 +454,394 @@ System.register(['aurelia-pal'], function (_export, _context) {
         });
       }
 
-      (function () {
-        var needsFix = false;
+      if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-        try {
-          var s = Object.keys('a');
-          needsFix = s.length !== 1 || s[0] !== '0';
-        } catch (e) {
-          needsFix = true;
-        }
+        (function () {
+          var needsFix = false;
 
-        if (needsFix) {
-          Object.keys = function () {
-            var hasOwnProperty = Object.prototype.hasOwnProperty,
-                hasDontEnumBug = !{ toString: null }.propertyIsEnumerable('toString'),
-                dontEnums = ['toString', 'toLocaleString', 'valueOf', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable', 'constructor'],
-                dontEnumsLength = dontEnums.length;
+          try {
+            var s = Object.keys('a');
+            needsFix = s.length !== 1 || s[0] !== '0';
+          } catch (e) {
+            needsFix = true;
+          }
 
-            return function (obj) {
-              if (obj === undefined || obj === null) {
-                throw TypeError('Cannot convert undefined or null to object');
-              }
+          if (needsFix) {
+            Object.keys = function () {
+              var hasOwnProperty = Object.prototype.hasOwnProperty,
+                  hasDontEnumBug = !{ toString: null }.propertyIsEnumerable('toString'),
+                  dontEnums = ['toString', 'toLocaleString', 'valueOf', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable', 'constructor'],
+                  dontEnumsLength = dontEnums.length;
 
-              obj = Object(obj);
+              return function (obj) {
+                if (obj === undefined || obj === null) {
+                  throw TypeError('Cannot convert undefined or null to object');
+                }
+
+                obj = Object(obj);
 
-              var result = [],
-                  prop,
-                  i;
+                var result = [],
+                    prop,
+                    i;
 
-              for (prop in obj) {
-                if (hasOwnProperty.call(obj, prop)) {
-                  result.push(prop);
+                for (prop in obj) {
+                  if (hasOwnProperty.call(obj, prop)) {
+                    result.push(prop);
+                  }
                 }
-              }
 
-              if (hasDontEnumBug) {
-                for (i = 0; i < dontEnumsLength; i++) {
-                  if (hasOwnProperty.call(obj, dontEnums[i])) {
-                    result.push(dontEnums[i]);
+                if (hasDontEnumBug) {
+                  for (i = 0; i < dontEnumsLength; i++) {
+                    if (hasOwnProperty.call(obj, dontEnums[i])) {
+                      result.push(dontEnums[i]);
+                    }
                   }
                 }
-              }
 
-              return result;
-            };
-          }();
-        }
-      })();
+                return result;
+              };
+            }();
+          }
+        })();
 
-      (function (O) {
-        if ('assign' in O) {
-          return;
-        }
+        (function (O) {
+          if ('assign' in O) {
+            return;
+          }
 
-        O.defineProperty(O, 'assign', {
-          configurable: true,
-          writable: true,
-          value: function () {
-            var gOPS = O.getOwnPropertySymbols,
-                pIE = O.propertyIsEnumerable,
-                filterOS = gOPS ? function (self) {
-              return gOPS(self).filter(pIE, self);
-            } : function () {
-              return Array.prototype;
-            };
+          O.defineProperty(O, 'assign', {
+            configurable: true,
+            writable: true,
+            value: function () {
+              var gOPS = O.getOwnPropertySymbols,
+                  pIE = O.propertyIsEnumerable,
+                  filterOS = gOPS ? function (self) {
+                return gOPS(self).filter(pIE, self);
+              } : function () {
+                return Array.prototype;
+              };
+
+              return function assign(where) {
+                if (gOPS && !(where instanceof O)) {
+                  console.warn('problematic Symbols', where);
+                }
 
-            return function assign(where) {
-              if (gOPS && !(where instanceof O)) {
-                console.warn('problematic Symbols', where);
-              }
+                function set(keyOrSymbol) {
+                  where[keyOrSymbol] = arg[keyOrSymbol];
+                }
 
-              function set(keyOrSymbol) {
-                where[keyOrSymbol] = arg[keyOrSymbol];
-              }
+                for (var i = 1, ii = arguments.length; i < ii; ++i) {
+                  var arg = arguments[i];
 
-              for (var i = 1, ii = arguments.length; i < ii; ++i) {
-                var arg = arguments[i];
+                  if (arg === null || arg === undefined) {
+                    continue;
+                  }
 
-                if (arg === null || arg === undefined) {
-                  continue;
+                  O.keys(arg).concat(filterOS(arg)).forEach(set);
                 }
 
-                O.keys(arg).concat(filterOS(arg)).forEach(set);
-              }
-
-              return where;
-            };
-          }()
-        });
-      })(Object);
+                return where;
+              };
+            }()
+          });
+        })(Object);
+      }
 
-      (function (global) {
-        var i;
+      if (typeof FEATURE_NO_ES2015 === 'undefined') {
 
-        var defineProperty = Object.defineProperty,
-            is = function is(a, b) {
-          return a === b || a !== a && b !== b;
-        };
+        (function (global) {
+          var i;
 
-        if (typeof WeakMap == 'undefined') {
-          global.WeakMap = createCollection({
-            'delete': sharedDelete,
+          var defineProperty = Object.defineProperty,
+              is = function is(a, b) {
+            return a === b || a !== a && b !== b;
+          };
 
-            clear: sharedClear,
+          if (typeof WeakMap == 'undefined') {
+            global.WeakMap = createCollection({
+              'delete': sharedDelete,
 
-            get: sharedGet,
+              clear: sharedClear,
 
-            has: mapHas,
+              get: sharedGet,
 
-            set: sharedSet
-          }, true);
-        }
+              has: mapHas,
 
-        if (typeof Map == 'undefined' || typeof new Map().values !== 'function' || !new Map().values().next) {
-          var _createCollection;
-
-          global.Map = createCollection((_createCollection = {
-            'delete': sharedDelete,
+              set: sharedSet
+            }, true);
+          }
 
-            has: mapHas,
+          if (typeof Map == 'undefined' || typeof new Map().values !== 'function' || !new Map().values().next) {
+            var _createCollection;
 
-            get: sharedGet,
+            global.Map = createCollection((_createCollection = {
+              'delete': sharedDelete,
 
-            set: sharedSet,
+              has: mapHas,
 
-            keys: sharedKeys,
+              get: sharedGet,
 
-            values: sharedValues,
+              set: sharedSet,
 
-            entries: mapEntries,
+              keys: sharedKeys,
 
-            forEach: sharedForEach,
+              values: sharedValues,
 
-            clear: sharedClear
-          }, _createCollection[Symbol.iterator] = mapEntries, _createCollection));
-        }
+              entries: mapEntries,
 
-        if (typeof Set == 'undefined' || typeof new Set().values !== 'function' || !new Set().values().next) {
-          var _createCollection2;
+              forEach: sharedForEach,
 
-          global.Set = createCollection((_createCollection2 = {
-            has: setHas,
+              clear: sharedClear
+            }, _createCollection[Symbol.iterator] = mapEntries, _createCollection));
+          }
 
-            add: sharedAdd,
+          if (typeof Set == 'undefined' || typeof new Set().values !== 'function' || !new Set().values().next) {
+            var _createCollection2;
 
-            'delete': sharedDelete,
+            global.Set = createCollection((_createCollection2 = {
+              has: setHas,
 
-            clear: sharedClear,
+              add: sharedAdd,
 
-            keys: sharedValues,
-            values: sharedValues,
+              'delete': sharedDelete,
 
-            entries: setEntries,
+              clear: sharedClear,
 
-            forEach: sharedForEach
-          }, _createCollection2[Symbol.iterator] = sharedValues, _createCollection2));
-        }
+              keys: sharedValues,
+              values: sharedValues,
 
-        if (typeof WeakSet == 'undefined') {
-          global.WeakSet = createCollection({
-            'delete': sharedDelete,
+              entries: setEntries,
 
-            add: sharedAdd,
+              forEach: sharedForEach
+            }, _createCollection2[Symbol.iterator] = sharedValues, _createCollection2));
+          }
 
-            clear: sharedClear,
+          if (typeof WeakSet == 'undefined') {
+            global.WeakSet = createCollection({
+              'delete': sharedDelete,
 
-            has: setHas
-          }, true);
-        }
+              add: sharedAdd,
 
-        function createCollection(proto, objectOnly) {
-          function Collection(a) {
-            if (!this || this.constructor !== Collection) return new Collection(a);
-            this._keys = [];
-            this._values = [];
-            this._itp = [];
-            this.objectOnly = objectOnly;
+              clear: sharedClear,
 
-            if (a) init.call(this, a);
+              has: setHas
+            }, true);
           }
 
-          if (!objectOnly) {
-            defineProperty(proto, 'size', {
-              get: sharedSize
-            });
-          }
+          function createCollection(proto, objectOnly) {
+            function Collection(a) {
+              if (!this || this.constructor !== Collection) return new Collection(a);
+              this._keys = [];
+              this._values = [];
+              this._itp = [];
+              this.objectOnly = objectOnly;
 
-          proto.constructor = Collection;
-          Collection.prototype = proto;
+              if (a) init.call(this, a);
+            }
 
-          return Collection;
-        }
+            if (!objectOnly) {
+              defineProperty(proto, 'size', {
+                get: sharedSize
+              });
+            }
 
-        function init(a) {
-          var i;
+            proto.constructor = Collection;
+            Collection.prototype = proto;
 
-          if (this.add) a.forEach(this.add, this);else a.forEach(function (a) {
-              this.set(a[0], a[1]);
-            }, this);
-        }
+            return Collection;
+          }
 
-        function sharedDelete(key) {
-          if (this.has(key)) {
-            this._keys.splice(i, 1);
-            this._values.splice(i, 1);
+          function init(a) {
+            var i;
 
-            this._itp.forEach(function (p) {
-              if (i < p[0]) p[0]--;
-            });
+            if (this.add) a.forEach(this.add, this);else a.forEach(function (a) {
+                this.set(a[0], a[1]);
+              }, this);
           }
 
-          return -1 < i;
-        };
+          function sharedDelete(key) {
+            if (this.has(key)) {
+              this._keys.splice(i, 1);
+              this._values.splice(i, 1);
 
-        function sharedGet(key) {
-          return this.has(key) ? this._values[i] : undefined;
-        }
+              this._itp.forEach(function (p) {
+                if (i < p[0]) p[0]--;
+              });
+            }
 
-        function has(list, key) {
-          if (this.objectOnly && key !== Object(key)) throw new TypeError("Invalid value used as weak collection key");
+            return -1 < i;
+          };
 
-          if (key != key || key === 0) for (i = list.length; i-- && !is(list[i], key);) {} else i = list.indexOf(key);
-          return -1 < i;
-        }
+          function sharedGet(key) {
+            return this.has(key) ? this._values[i] : undefined;
+          }
 
-        function setHas(value) {
-          return has.call(this, this._values, value);
-        }
+          function has(list, key) {
+            if (this.objectOnly && key !== Object(key)) throw new TypeError("Invalid value used as weak collection key");
 
-        function mapHas(value) {
-          return has.call(this, this._keys, value);
-        }
+            if (key != key || key === 0) for (i = list.length; i-- && !is(list[i], key);) {} else i = list.indexOf(key);
+            return -1 < i;
+          }
 
-        function sharedSet(key, value) {
-          this.has(key) ? this._values[i] = value : this._values[this._keys.push(key) - 1] = value;
-          return this;
-        }
+          function setHas(value) {
+            return has.call(this, this._values, value);
+          }
 
-        function sharedAdd(value) {
-          if (!this.has(value)) this._values.push(value);
-          return this;
-        }
+          function mapHas(value) {
+            return has.call(this, this._keys, value);
+          }
 
-        function sharedClear() {
-          (this._keys || 0).length = this._values.length = 0;
-        }
+          function sharedSet(key, value) {
+            this.has(key) ? this._values[i] = value : this._values[this._keys.push(key) - 1] = value;
+            return this;
+          }
 
-        function sharedKeys() {
-          return sharedIterator(this._itp, this._keys);
-        }
+          function sharedAdd(value) {
+            if (!this.has(value)) this._values.push(value);
+            return this;
+          }
 
-        function sharedValues() {
-          return sharedIterator(this._itp, this._values);
-        }
+          function sharedClear() {
+            (this._keys || 0).length = this._values.length = 0;
+          }
 
-        function mapEntries() {
-          return sharedIterator(this._itp, this._keys, this._values);
-        }
+          function sharedKeys() {
+            return sharedIterator(this._itp, this._keys);
+          }
 
-        function setEntries() {
-          return sharedIterator(this._itp, this._values, this._values);
-        }
+          function sharedValues() {
+            return sharedIterator(this._itp, this._values);
+          }
 
-        function sharedIterator(itp, array, array2) {
-          var _ref;
+          function mapEntries() {
+            return sharedIterator(this._itp, this._keys, this._values);
+          }
 
-          var p = [0],
-              done = false;
-          itp.push(p);
-          return _ref = {}, _ref[Symbol.iterator] = function () {
-            return this;
-          }, _ref.next = function next() {
-            var v,
-                k = p[0];
-            if (!done && k < array.length) {
-              v = array2 ? [array[k], array2[k]] : array[k];
-              p[0]++;
-            } else {
-              done = true;
-              itp.splice(itp.indexOf(p), 1);
-            }
-            return { done: done, value: v };
-          }, _ref;
-        }
+          function setEntries() {
+            return sharedIterator(this._itp, this._values, this._values);
+          }
 
-        function sharedSize() {
-          return this._values.length;
-        }
+          function sharedIterator(itp, array, array2) {
+            var _ref;
+
+            var p = [0],
+                done = false;
+            itp.push(p);
+            return _ref = {}, _ref[Symbol.iterator] = function () {
+              return this;
+            }, _ref.next = function next() {
+              var v,
+                  k = p[0];
+              if (!done && k < array.length) {
+                v = array2 ? [array[k], array2[k]] : array[k];
+                p[0]++;
+              } else {
+                done = true;
+                itp.splice(itp.indexOf(p), 1);
+              }
+              return { done: done, value: v };
+            }, _ref;
+          }
 
-        function sharedForEach(callback, context) {
-          var it = this.entries();
-          for (;;) {
-            var r = it.next();
-            if (r.done) break;
-            callback.call(context, r.value[1], r.value[0], this);
+          function sharedSize() {
+            return this._values.length;
           }
-        }
-      })(PLATFORM.global);
 
-      emptyMetadata = Object.freeze({});
-      metadataContainerKey = '__metadata__';
-      bind = Function.prototype.bind;
+          function sharedForEach(callback, context) {
+            var it = this.entries();
+            for (;;) {
+              var r = it.next();
+              if (r.done) break;
+              callback.call(context, r.value[1], r.value[0], this);
+            }
+          }
+        })(PLATFORM.global);
+      }
 
+      if (typeof FEATURE_NO_ES2015 === 'undefined') {
+        (function () {
 
-      if (typeof PLATFORM.global.Reflect === 'undefined') {
-        PLATFORM.global.Reflect = {};
-      }
+          var bind = Function.prototype.bind;
 
-      if (typeof Reflect.getOwnMetadata !== 'function') {
-        Reflect.getOwnMetadata = function (metadataKey, target, targetKey) {
-          if (target.hasOwnProperty(metadataContainerKey)) {
-            return (target[metadataContainerKey][targetKey] || emptyMetadata)[metadataKey];
+          if (typeof PLATFORM.global.Reflect === 'undefined') {
+            PLATFORM.global.Reflect = {};
           }
-        };
-      }
 
-      if (typeof Reflect.defineMetadata !== 'function') {
-        Reflect.defineMetadata = function (metadataKey, metadataValue, target, targetKey) {
-          var metadataContainer = target.hasOwnProperty(metadataContainerKey) ? target[metadataContainerKey] : target[metadataContainerKey] = {};
-          var targetContainer = metadataContainer[targetKey] || (metadataContainer[targetKey] = {});
-          targetContainer[metadataKey] = metadataValue;
-        };
-      }
+          if (typeof Reflect.defineProperty !== 'function') {
+            Reflect.defineProperty = function (target, propertyKey, descriptor) {
+              if ((typeof target === 'undefined' ? 'undefined' : _typeof(target)) === 'object' ? target === null : typeof target !== 'function') {
+                throw new TypeError('Reflect.defineProperty called on non-object');
+              }
+              try {
+                Object.defineProperty(target, propertyKey, descriptor);
+                return true;
+              } catch (e) {
+                return false;
+              }
+            };
+          }
 
-      if (typeof Reflect.metadata !== 'function') {
-        Reflect.metadata = function (metadataKey, metadataValue) {
-          return function (target, targetKey) {
-            Reflect.defineMetadata(metadataKey, metadataValue, target, targetKey);
-          };
-        };
-      }
+          if (typeof Reflect.construct !== 'function') {
+            Reflect.construct = function (Target, args) {
+              if (args) {
+                switch (args.length) {
+                  case 0:
+                    return new Target();
+                  case 1:
+                    return new Target(args[0]);
+                  case 2:
+                    return new Target(args[0], args[1]);
+                  case 3:
+                    return new Target(args[0], args[1], args[2]);
+                  case 4:
+                    return new Target(args[0], args[1], args[2], args[3]);
+                }
+              }
 
-      if (typeof Reflect.defineProperty !== 'function') {
-        Reflect.defineProperty = function (target, propertyKey, descriptor) {
-          if ((typeof target === 'undefined' ? 'undefined' : _typeof(target)) === 'object' ? target === null : typeof target !== 'function') {
-            throw new TypeError('Reflect.defineProperty called on non-object');
+              var a = [null];
+              a.push.apply(a, args);
+              return new (bind.apply(Target, a))();
+            };
           }
-          try {
-            Object.defineProperty(target, propertyKey, descriptor);
-            return true;
-          } catch (e) {
-            return false;
+
+          if (typeof Reflect.ownKeys !== 'function') {
+            Reflect.ownKeys = function (o) {
+              return Object.getOwnPropertyNames(o).concat(Object.getOwnPropertySymbols(o));
+            };
           }
-        };
+        })();
       }
 
-      if (typeof Reflect.construct !== 'function') {
-        Reflect.construct = function (Target, args) {
-          if (args) {
-            switch (args.length) {
-              case 0:
-                return new Target();
-              case 1:
-                return new Target(args[0]);
-              case 2:
-                return new Target(args[0], args[1]);
-              case 3:
-                return new Target(args[0], args[1], args[2]);
-              case 4:
-                return new Target(args[0], args[1], args[2], args[3]);
-            }
+      if (typeof FEATURE_NO_ESNEXT === 'undefined') {
+        (function () {
+
+          var emptyMetadata = Object.freeze({});
+          var metadataContainerKey = '__metadata__';
+
+          if (typeof Reflect.getOwnMetadata !== 'function') {
+            Reflect.getOwnMetadata = function (metadataKey, target, targetKey) {
+              if (target.hasOwnProperty(metadataContainerKey)) {
+                return (target[metadataContainerKey][targetKey] || emptyMetadata)[metadataKey];
+              }
+            };
           }
 
-          var a = [null];
-          a.push.apply(a, args);
-          return new (bind.apply(Target, a))();
-        };
-      }
+          if (typeof Reflect.defineMetadata !== 'function') {
+            Reflect.defineMetadata = function (metadataKey, metadataValue, target, targetKey) {
+              var metadataContainer = target.hasOwnProperty(metadataContainerKey) ? target[metadataContainerKey] : target[metadataContainerKey] = {};
+              var targetContainer = metadataContainer[targetKey] || (metadataContainer[targetKey] = {});
+              targetContainer[metadataKey] = metadataValue;
+            };
+          }
 
-      if (typeof Reflect.ownKeys !== 'function') {
-        Reflect.ownKeys = function (o) {
-          return Object.getOwnPropertyNames(o).concat(Object.getOwnPropertySymbols(o));
-        };
+          if (typeof Reflect.metadata !== 'function') {
+            Reflect.metadata = function (metadataKey, metadataValue) {
+              return function (target, targetKey) {
+                Reflect.defineMetadata(metadataKey, metadataValue, target, targetKey);
+              };
+            };
+          }
+        })();
       }
     }
   };
diff --git a/doc/CHANGELOG.md b/doc/CHANGELOG.md
index 74ef314..496e9a6 100644
--- a/doc/CHANGELOG.md
+++ b/doc/CHANGELOG.md
@@ -1,3 +1,10 @@
+<a name="1.2.0"></a>
+# [1.2.0](https://github.com/aurelia/polyfills/compare/1.1.1...v1.2.0) (2017-02-21)
+
+### Features
+
+* opt-out for polyfills
+
 <a name="1.1.1"></a>
 ## [1.1.1](https://github.com/aurelia/polyfills/compare/1.1.0...v1.1.1) (2016-09-13)
 
diff --git a/package.json b/package.json
index f83306a..cd980b5 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "aurelia-polyfills",
-  "version": "1.1.1",
+  "version": "1.2.0",
   "description": "The minimal set of polyfills that the Aurelia platform needs to run on ES5 browsers.",
   "keywords": [
     "aurelia",