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/compiler/test/template_parser_spec.ts

@@ -12,10 +12,10 @@ import {ElementSchemaRegistry} from '@angular/compiler/src/schema/element_schema
 import {AttrAst, BoundDirectivePropertyAst, BoundElementPropertyAst, BoundEventAst, BoundTextAst, DirectiveAst, ElementAst, EmbeddedTemplateAst, NgContentAst, PropertyBindingType, ProviderAstType, ReferenceAst, TemplateAst, TemplateAstVisitor, TextAst, VariableAst, templateVisitAll} from '@angular/compiler/src/template_ast';
 import {TEMPLATE_TRANSFORMS, TemplateParser, splitClasses} from '@angular/compiler/src/template_parser';
 import {MockSchemaRegistry} from '@angular/compiler/testing';
+import {SecurityContext} from '@angular/core';
 import {Console} from '@angular/core/src/console';
 import {afterEach, beforeEach, beforeEachProviders, ddescribe, describe, expect, iit, inject, it, xit} from '@angular/core/testing/testing_internal';
 
-import {SecurityContext} from '../core_private';
 import {Identifiers, identifierToken} from '../src/identifiers';
 import {DEFAULT_INTERPOLATION_CONFIG, InterpolationConfig} from '../src/interpolation_config';