feat(query): adds initial implementation of the query api.

Queries allow a directive to inject a live list of directives of a given
type from its LightDom. The injected list is Iterable (in JS and Dart).
It will be Observable when Observables are support in JS, for now it
maintains a simple list of onChange callbacks API.

To support queries, element injectors now maintain a list of
child injectors in the correct DOM order (dynamically updated by
viewports).

For performance reasons we allow only 3 active queries in an injector
subtree. The feature adds no overhead to the application when not
used. Queries walk the injector tree only during dynamic view
addition/removal as triggered by viewport directives.

Syncs changes between viewContainer on the render and logic sides.

Closes #792

modules/angular2/src/render/dom/view/view_container.js

@@ -122,6 +122,7 @@ export class ViewContainer {
     return r;
   }
 
+
   static moveViewNodesAfterSibling(sibling, view) {
     for (var i = view.rootNodes.length - 1; i >= 0; --i) {
       DOM.insertAfter(sibling, view.rootNodes[i]);