fix(merge): treat dates as atomic values instead of objects.

Makes angular.merge copy dates correctly.

Author: gabrielmaldi

src/Angular.js

@@ -334,7 +334,7 @@ function baseExtend(dst, objs, deep) {
       var key = keys[j];
       var src = obj[key];
 
-      if (deep && isObject(src)) {
+      if (deep && isObject(src) && !isDate(src)) {
         if (!isObject(dst[key])) dst[key] = isArray(src) ? [] : {};
         baseExtend(dst[key], [src], true);
       } else {