refactor(compiler): remove Viewport directives, use Decorator instead

BREAKING_CHANGE:
- The special type of `Viewport` directives is removed
  in favor of a more general `Decorator` directive
- `ViewContainerRef` now no more has a default `ProtoViewRef`
  but requires an explicit one when creating views.

Closes #1536

modules/angular2/src/router/router_outlet.js

@@ -32,7 +32,7 @@ export class RouterOutlet {
       ]);
 
       this._viewContainer.clear();
-      this._viewContainer.create(0, pv, outletInjector);
+      this._viewContainer.create(pv, 0, outletInjector);
     });
   }