feat(decorators): adds support for parameter decorators.

Paramater decorators expect to be called as currently implemented by TS.

modules/angular2/src/facade/lang.dart

@@ -217,3 +217,6 @@ class DateWrapper {
     return date.toUtc().toIso8601String();
   }
 }
+
+// needed to match the exports from lang.js
+var global = null;