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_material/src/components/dialog/dialog.ts

@@ -1,16 +1,20 @@
 import {
+  bind,
+  forwardRef,
   Component,
-  Directive,
-  View,
-  ViewEncapsulation,
-  Host,
-  SkipSelf,
-  ElementRef,
-  DynamicComponentLoader,
   ComponentRef,
-  DomRenderer
-} from 'angular2/angular2';
-import {bind, Injectable, forwardRef, ResolvedBinding, Injector} from 'angular2/di';
+  Directive,
+  DynamicComponentLoader,
+  ElementRef,
+  Host,
+  Injectable,
+  ResolvedBinding,
+  SkipSelf,
+  Injector,
+  View,
+  ViewEncapsulation
+} from 'angular2/core';
+import {DomRenderer} from 'angular2/render';
 
 import {ObservableWrapper, Promise, PromiseWrapper} from 'angular2/src/core/facade/async';
 import {isPresent, Type} from 'angular2/src/core/facade/lang';