fix(AnonymousSubject): is now exposed on Rx namespace

fixes #2002

Author: benlesh

spec/Subject-spec.ts

@@ -524,6 +524,10 @@ describe('Subject', () => {
 });
 
 describe('AnonymousSubject', () => {
+  it('should be exposed', () => {
+    expect(Rx.AnonymousSubject).to.be.a('function');
+  });
+
   it('should not eager', () => {
     let subscribed = false;
 

src/Rx.ts

@@ -2,7 +2,7 @@
 // Subject imported before Observable to bypass circular dependency issue since
 // Subject extends Observable and Observable references Subject in it's
 // definition
-export {Subject} from './Subject';
+export {Subject, AnonymousSubject} from './Subject';
 /* tslint:enable:no-unused-variable */
 export {Observable} from './Observable';