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/http/backends/browser_jsonp.ts

@@ -1,4 +1,4 @@
-import {Injectable} from 'angular2/di';
+import {Injectable} from 'angular2/src/core/di';
 import {global} from 'angular2/src/core/facade/lang';
 
 let _nextRequestId = 0;

modules/angular2/src/http/backends/browser_xhr.ts

@@ -1,4 +1,4 @@
-import {Injectable} from 'angular2/di';
+import {Injectable} from 'angular2/src/core/di';
 
 // Make sure not to evaluate this in a non-browser environment!
 @Injectable()

modules/angular2/src/http/backends/jsonp_backend.ts

@@ -3,7 +3,7 @@ import {ReadyStates, RequestMethods} from '../enums';
 import {Request} from '../static_request';
 import {Response} from '../static_response';
 import {ResponseOptions, BaseResponseOptions} from '../base_response_options';
-import {Injectable} from 'angular2/di';
+import {Injectable} from 'angular2/src/core/di';
 import {BrowserJsonp} from './browser_jsonp';
 import {EventEmitter, ObservableWrapper} from 'angular2/src/core/facade/async';
 import {StringWrapper, isPresent, makeTypeError} from 'angular2/src/core/facade/lang';

modules/angular2/src/http/backends/mock_backend.ts

@@ -1,4 +1,4 @@
-import {Injectable} from 'angular2/di';
+import {Injectable} from 'angular2/src/core/di';
 import {Request} from '../static_request';
 import {Response} from '../static_response';
 import {ReadyStates} from '../enums';
@@ -139,7 +139,7 @@ export class MockBackend implements ConnectionBackend {
    *
    * ```
    * import {MockBackend, Http, BaseRequestOptions} from 'angular2/http';
-   * import {Injector} from 'angular2/di';
+   * import {Injector} from 'angular2/core';
    *
    * it('should get a response', () => {
    *   var connection; //this will be set when a new connection is emitted from the backend.

modules/angular2/src/http/backends/xhr_backend.ts

@@ -3,7 +3,7 @@ import {ReadyStates, RequestMethods, ResponseTypes} from '../enums';
 import {Request} from '../static_request';
 import {Response} from '../static_response';
 import {ResponseOptions, BaseResponseOptions} from '../base_response_options';
-import {Injectable} from 'angular2/di';
+import {Injectable} from 'angular2/src/core/di';
 import {BrowserXhr} from './browser_xhr';
 import {EventEmitter, ObservableWrapper} from 'angular2/src/core/facade/async';
 import {isPresent} from 'angular2/src/core/facade/lang';

modules/angular2/src/http/base_request_options.ts

@@ -2,7 +2,7 @@ import {CONST_EXPR, CONST, isPresent, isString} from 'angular2/src/core/facade/l
 import {Headers} from './headers';
 import {RequestModesOpts, RequestMethods, RequestCacheOpts, RequestCredentialsOpts} from './enums';
 import {RequestOptionsArgs} from './interfaces';
-import {Injectable} from 'angular2/di';
+import {Injectable} from 'angular2/src/core/di';
 import {URLSearchParams} from './url_search_params';
 
 /**

modules/angular2/src/http/base_response_options.ts

@@ -1,4 +1,4 @@
-import {Injectable} from 'angular2/di';
+import {Injectable} from 'angular2/src/core/di';
 import {isPresent, isJsObject} from 'angular2/src/core/facade/lang';
 import {Headers} from './headers';
 import {ResponseTypes} from './enums';