refactor: export core APIs from angular2/core

This change moves many APIs to the angular2/core export.

This change also automatically adds FORM_BINDINGS in
the application root injector.

BREAKING CHANGE:
    Many dependencies that were previously exported from specific
    APIs are now exported from angular2/core. Affected exports, which
    should now be included from angular2/core include:

    angular2/forms
    angular2/di
    angular2/directives
    angular2/change_detection
    angular2/bootstrap (except for dart users)
    angular2/render
    angular2/metadata
    angular2/debug
    angular2/pipes
Closes #3977

modules/angular2/src/core/render.ts

@@ -0,0 +1,16 @@
+// Public API for render
+export {
+  RenderDirectiveMetadata,
+  DomRenderer,
+  RenderEventDispatcher,
+  Renderer,
+  RenderElementRef,
+  RenderViewRef,
+  RenderProtoViewRef,
+  RenderFragmentRef,
+  RenderViewWithFragments,
+  ViewDefinition,
+  DOCUMENT,
+  APP_ID,
+  MAX_IN_MEMORY_ELEMENTS_PER_TEMPLATE
+} from './render/render';