refactor(core): introduce ViewRef and ProtoViewRef

BREAKING CHANGES:
- `NgElement` merged into `ElementRef`
- `Compiler.compile…` returns `ProtoViewRef`
- `ViewContainer` uses `ProtoViewRef`s and `ViewRef`s.
- `ViewRef`/`ProtoViewRef` in renderer were renamed to
  `RenderViewRef`/`RenderProtoViewRef`.

Related to #1477
Closes #1592

modules/angular2/src/directives/class.js

@@ -1,7 +1,7 @@
 import {Decorator} from 'angular2/src/core/annotations/annotations';
 import {isPresent} from 'angular2/src/facade/lang';
 import {DOM} from 'angular2/src/dom/dom_adapter';
-import {NgElement} from 'angular2/src/core/compiler/ng_element';
+import {ElementRef} from 'angular2/src/core/compiler/element_ref';
 
 @Decorator({
   selector: '[class]',
@@ -11,7 +11,7 @@ import {NgElement} from 'angular2/src/core/compiler/ng_element';
 })
 export class CSSClass {
   _domEl;
-  constructor(ngEl: NgElement) {
+  constructor(ngEl: ElementRef) {
     this._domEl = ngEl.domElement;
   }
 

modules/angular2/src/directives/for.js

@@ -1,6 +1,6 @@
 import {Viewport} from 'angular2/src/core/annotations/annotations';
 import {ViewContainerRef} from 'angular2/src/core/compiler/view_container_ref';
-import {AppView} from 'angular2/src/core/compiler/view';
+import {ViewRef} from 'angular2/src/core/compiler/view_ref';
 import {isPresent, isBlank} from 'angular2/src/facade/lang';
 import {ListWrapper} from 'angular2/src/facade/collection';
 
@@ -114,7 +114,7 @@ export class For  {
 }
 
 class RecordViewTuple {
-  view: AppView;
+  view: ViewRef;
   record: any;
   constructor(record, view) {
     this.record = record;