chore(build): Upgrade to TypeScript@1.5.3

This change also makes us compliant with 1.6.0-dev compiler,
so we can do some experiments with apps that use 1.6 features
and compile against Angular.

We should probably add a travis build for 1.6 so we stay compatible
with both versions.

modules/angular2/src/mock/location_mock.ts

@@ -6,7 +6,7 @@ import {List, ListWrapper} from 'angular2/src/facade/collection';
 import {Location} from 'angular2/src/router/location';
 
 
-@proxy
+@proxy()
 @IMPLEMENTS(Location)
 export class SpyLocation extends SpyObject {
   urlChanges: List<string>;