refactor(core): move facades out of core

This is part of ongoing work to make core platform-independent.

BREAKING CHANGE

All private exports from 'angular2/src/core/facade/{lang,collection,exception_handler}' should be replaced with 'angular2/src/facade/{lang,collection,exception_handler}'.

modules/playground/e2e_test/hash_routing/hash_location_spec.ts

@@ -1,5 +1,5 @@
 import {verifyNoBrowserErrors} from 'angular2/src/testing/e2e_util';
-import {Promise} from 'angular2/src/core/facade/async';
+import {Promise} from 'angular2/src/facade/async';
 
 function waitForElement(selector) {
   var EC = (<any>protractor).ExpectedConditions;