refactor(linker): Expose ViewResolver to public api

Fixes https://github.com/angular/angular/issues/4780

Closes #4789

modules/angular2/src/core/linker.ts

@@ -10,6 +10,7 @@ export {
   DoCheck
 } from './linker/interfaces';
 export {DirectiveResolver} from './linker/directive_resolver';
+export {ViewResolver} from './linker/view_resolver';
 export {Compiler} from './linker/compiler';
 export {AppViewManager} from './linker/view_manager';
 export {QueryList} from './linker/query_list';