fix: only versions of angular >= 2.0.0 are supported

BREAKING CHANGE:

no RC versions of angular are supported. This was probably introduced in 0.2.x of this module, but clarifying here as a distinct breaking change

Closes #66

package.json

@@ -105,9 +105,9 @@
     "zone.js": "~0.6.12"
   },
   "peerDependencies": {
-    "@angular/core": "^2.0.0-rc.5",
-    "@angular/common": "^2.0.0-rc.5",
-    "@angular/platform-browser": "^2.0.0-rc.5"
+    "@angular/core": "^2.0.0",
+    "@angular/common": "^2.0.0",
+    "@angular/platform-browser": "^2.0.0"
   },
   "files": [
     "dist",