docs(*): add @publicModule tags

Initial set of tags to demonstrate the public docs filtering

Closes #988

modules/angular2/src/core/dom/element.js

@@ -1,6 +1,9 @@
 import {DOM} from 'angular2/src/dom/dom_adapter';
 import {normalizeBlank} from 'angular2/src/facade/lang';
 
+/**
+ * @publicModule angular2/angular2
+ */
 export class NgElement {
   domElement;
   constructor(domElement) {