feat(browser): use AppModules for bootstrap in the browser

This introduces the `BrowserModule` to be used for long form
bootstrap and offline compile bootstrap:

```
@AppModule({
  modules: [BrowserModule],
  precompile: [MainComponent],
  providers: […], // additional providers
  directives: […], // additional platform directives
  pipes: […] // additional platform pipes
})
class MyModule {
  constructor(appRef: ApplicationRef) {
    appRef.bootstrap(MainComponent);
  }
}

// offline compile
import {bootstrapModuleFactory} from ‘@angular/platform-browser’;
bootstrapModuleFactory(MyModuleNgFactory);

// runtime compile long form
import {bootstrapModule} from ‘@angular/platform-browser-dynamic’;
bootstrapModule(MyModule);
```

The short form, `bootstrap(...)`, can now creates a module on the fly,
given `directives`, `pipes, `providers`, `precompile` and `modules`
properties.

Related changes:
- make `SanitizationService`, `SecurityContext` public in `@angular/core` so that the offline compiler can resolve the token
- move `AnimationDriver` to `platform-browser` and make it
  public so that the offline compiler can resolve the token

BREAKING CHANGES:
- short form bootstrap does no longer allow
  to inject compiler internals (i.e. everything 
  from `@angular/compiler). Inject `Compiler` instead.
  To provide custom providers for the compiler,
  create a custom compiler via `browserCompiler({providers: [...]})`
  and pass that into the `bootstrap` method.

modules/@angular/core/src/animation/animation_driver.ts

@@ -1,25 +0,0 @@
-/**
- * @license
- * Copyright Google Inc. All Rights Reserved.
- *
- * Use of this source code is governed by an MIT-style license that can be
- * found in the LICENSE file at https://angular.io/license
- */
-
-import {AnimationKeyframe} from './animation_keyframe';
-import {AnimationPlayer, NoOpAnimationPlayer} from './animation_player';
-import {AnimationStyles} from './animation_styles';
-
-export abstract class AnimationDriver {
-  abstract animate(
-      element: any, startingStyles: AnimationStyles, keyframes: AnimationKeyframe[],
-      duration: number, delay: number, easing: string): AnimationPlayer;
-}
-
-export class NoOpAnimationDriver extends AnimationDriver {
-  animate(
-      element: any, startingStyles: AnimationStyles, keyframes: AnimationKeyframe[],
-      duration: number, delay: number, easing: string): AnimationPlayer {
-    return new NoOpAnimationPlayer();
-  }
-}