feat(view): reimplemented property setters using change detection

modules/angular2/src/di/key.js

@@ -1,5 +1,5 @@
 import {MapWrapper} from 'angular2/src/facade/collection';
-//import {int} from 'angular2/src/facade/lang';
+import {stringify} from 'angular2/src/facade/lang';
 
 // TODO: uncoment `int` once https://github.com/angular/angular/issues/1414 is fixed
 
@@ -23,6 +23,10 @@ export class Key {
     this.id = id;
   }
 
+  get displayName() {
+    return stringify(this.token);
+  }
+
   /**
    * Retrieves a `Key` for a token.
    */