Add shim for es5

Author: Lee Richmond

package.json

@@ -41,6 +41,7 @@
   },
   "dependencies": {
     "es6-promise": "^4.0.5",
-    "lodash-es": "^4.17.4"
+    "lodash-es": "^4.17.4",
+    "object-assign-shim": "1.0.0"
   }
 }

src/main.ts

@@ -1,5 +1,6 @@
 /// <reference path="../types/index.d.ts" />
 
+import 'object-assign-shim'
 import * as es6Promise from 'es6-promise';
 es6Promise.polyfill();