docs(type): Export Type so that we can link to it in our docs.

Closes #3345

modules/angular2/core.ts

@@ -5,6 +5,7 @@
  */
 export {appComponentTypeToken} from 'angular2/src/core/application_tokens';
 export {ApplicationRef} from 'angular2/src/core/application_common';
+export {Type} from 'angular2/src/facade/lang';
 
 
 // Compiler Related Dependencies.

modules/angular2/src/facade/lang.ts

@@ -3,7 +3,13 @@ var _global: BrowserNodeGlobal = <any>(typeof window === 'undefined' ? global :
 export {_global as global};
 
 export var Type = Function;
-export type Type = new (...args: any[]) => any;
+
+/**
+ * Runtime representation of a type.
+ *
+ * In JavaScript a Type is a constructor function.
+ */
+export interface Type extends Function { new (...args): any; }
 
 export function getTypeNameForDebugging(type: Type): string {
   return type['name'];