refactor(async): refactor EventEmitter

Refactor EventEmitter and Async Facade to match ES7 Observable semantics, properly use RxJS typedefs, make EventEmitter inherit from RxJS Subject. Closes #4149.

BREAKING CHANGE:
- consumers of EventEmitter no longer need to call .toRx()
- EventEmitter is now generic and requires a type - e.g. `EventEmitter<string>`
- EventEmitter and Observable now use the `.subscribe(generatorOrNext, error, complete)` method instead of `.observer(generator)`
- ObservableWrapper uses `callNext/callError/callComplete` instead of `callNext/callThrow/callReturn`

modules/angular2/test/core/debug/debug_element_spec.ts

@@ -89,7 +89,7 @@ class ParentComp {
 @Directive({selector: 'custom-emitter', outputs: ['myevent']})
 @Injectable()
 class CustomEmitter {
-  myevent: EventEmitter;
+  myevent: EventEmitter<any>;
 
   constructor() { this.myevent = new EventEmitter(); }
 }

modules/angular2/test/core/facade/async_spec.ts

@@ -16,7 +16,7 @@ import {ObservableWrapper, EventEmitter, PromiseWrapper} from 'angular2/src/core
 
 export function main() {
   describe('EventEmitter', () => {
-    var emitter: EventEmitter;
+    var emitter: EventEmitter<any>;
 
     beforeEach(() => { emitter = new EventEmitter(); });
 
@@ -34,18 +34,18 @@ export function main() {
            expect(error).toEqual("Boom");
            async.done();
          });
-         ObservableWrapper.callThrow(emitter, "Boom");
+         ObservableWrapper.callError(emitter, "Boom");
        }));
 
     it("should work when no throw callback is provided", inject([AsyncTestCompleter], (async) => {
          ObservableWrapper.subscribe(emitter, (_) => {}, (_) => { async.done(); });
-         ObservableWrapper.callThrow(emitter, "Boom");
+         ObservableWrapper.callError(emitter, "Boom");
        }));
 
     it("should call the return callback", inject([AsyncTestCompleter], (async) => {
          ObservableWrapper.subscribe(emitter, (_) => {}, (_) => {}, () => { async.done(); });
 
-         ObservableWrapper.callReturn(emitter);
+         ObservableWrapper.callComplete(emitter);
        }));
 
     it("should subscribe to the wrapper asynchronously", () => {

modules/angular2/test/core/forms/integration_spec.ts

@@ -907,7 +907,7 @@ class WrappedValue implements ControlValueAccessor {
 
 @Component({selector: "my-input", template: ''})
 class MyInput implements ControlValueAccessor {
-  @Output('change') onChange: EventEmitter = new EventEmitter();
+  @Output('change') onChange: EventEmitter<any> = new EventEmitter();
   value: string;
 
   constructor(cd: NgControl) { cd.valueAccessor = this; }

modules/angular2/test/core/forms/model_spec.ts

@@ -133,7 +133,7 @@ export function main() {
         if (!IS_DART) {
           it("should update set errors and status before emitting an event",
              inject([AsyncTestCompleter], (async) => {
-               c.valueChanges.toRx().subscribe(value => {
+               c.valueChanges.subscribe(value => {
                  expect(c.valid).toEqual(false);
                  expect(c.errors).toEqual({"required": true});
                  async.done();

modules/angular2/test/core/linker/integration_spec.ts

@@ -1976,7 +1976,7 @@ class DoublePipe implements PipeTransform {
 @Injectable()
 class DirectiveEmitingEvent {
   msg: string;
-  event: EventEmitter;
+  event: EventEmitter<any>;
 
   constructor() {
     this.msg = '';
@@ -2002,7 +2002,7 @@ class DirectiveUpdatingHostProperties {
 @Directive({selector: '[update-host-actions]', host: {'@setAttr': 'setAttribute'}})
 @Injectable()
 class DirectiveUpdatingHostActions {
-  setAttr: EventEmitter;
+  setAttr: EventEmitter<any>;
 
   constructor() { this.setAttr = new EventEmitter(); }