feat(di): Mark objects @Injectable

Allow `PrivateComponentLoader`, `Testability`, and `TestabilityRegistry` to be injected.

Author: Tim Blasi

modules/angular2/src/core/compiler/private_component_loader.js

@@ -1,12 +1,14 @@
 import {Compiler} from './compiler';
 import {ShadowDomStrategy} from './shadow_dom_strategy';
+import {Injectable} from 'angular2/di';
 import {EventManager} from 'angular2/src/render/dom/events/event_manager';
 import {DirectiveMetadataReader} from 'angular2/src/core/compiler/directive_metadata_reader';
 import {Component} from 'angular2/src/core/annotations/annotations';
 import {PrivateComponentLocation} from './private_component_location';
 import {Type, stringify, BaseException} from 'angular2/src/facade/lang';
 
 
+@Injectable()
 export class PrivateComponentLoader {
  compiler:Compiler;
  shadowDomStrategy:ShadowDomStrategy;

modules/angular2/src/core/testability/testability.js

@@ -1,3 +1,4 @@
+import {Injectable} from 'angular2/di';
 import {DOM} from 'angular2/src/dom/dom_adapter';
 import {Map, MapWrapper, List, ListWrapper} from 'angular2/src/facade/collection';
 import {StringWrapper, isBlank, BaseException} from 'angular2/src/facade/lang';
@@ -9,6 +10,7 @@ import * as getTestabilityModule from 'angular2/src/core/testability/get_testabi
  * the browser and by services such as Protractor. Each bootstrapped Angular
  * application on the page will have an instance of Testability.
  */
+@Injectable()
 export class Testability {
  _pendingCount: number;
  _callbacks: List;
@@ -53,6 +55,7 @@ export class Testability {
  }
 }
 
+@Injectable()
 export class TestabilityRegistry {
  _applications: Map;