fixed(spy): support `SpyObject` in Typescript as well

- allow `@IMPLEMENTS` as a decorator
- implement empty `noSuchMethod`

modules/angular2/src/facade/lang.ts

@@ -45,7 +45,12 @@ export function CONST() {
 
 export class ABSTRACT {}
 
-export class IMPLEMENTS {}
+// Note: This is only a marker annotation needed for ts2dart.
+// This is written so that is can be used as a Traceur annotation
+// or a Typescript decorator.
+export function IMPLEMENTS(_) {
+  return (t) => t;
+}
 
 export function isPresent(obj): boolean {
   return obj !== undefined && obj !== null;

modules/angular2/src/test_lib/test_lib.ts

@@ -299,6 +299,9 @@ export class SpyObject {
       }
     }
   }
+  // Noop so that SpyObject has the smae interface as in Dart
+  noSuchMethod(args) {}
+
   spy(name) {
     if (!this[name]) {
       this[name] = this._createGuinnessCompatibleSpy(name);