refactor(EventEmitter): rename .next() to .emit()

BREAKING CHANGE:

EventEmitter#next(value) is deprecated, use EventEmitter#emit(value)
instead.

Closes #4287

Closes #5302

modules/angular2/src/facade/async.dart

@@ -46,9 +46,14 @@ class ObservableWrapper {
     s.cancel();
   }
 
+  @Deprecated('Use callEmit() instead')
   static void callNext(EventEmitter emitter, value) {
     emitter.add(value);
   }
+  
+  static void callEmit(EventEmitter emitter, value) {
+    emitter.add(value);
+  }
 
   static void callError(EventEmitter emitter, error) {
     emitter.addError(error);
@@ -85,6 +90,10 @@ class EventEmitter<T> extends Stream<T> {
   void add(value) {
     _controller.add(value);
   }
+  
+  void emit(value) {
+    _controller.add(value);
+  }
 
   void addError(error) {
     _controller.addError(error);

modules/angular2/src/facade/async.ts

@@ -39,8 +39,13 @@ export class ObservableWrapper {
 
   static dispose(subscription: any) { subscription.unsubscribe(); }
 
+  /**
+   * @deprecated - use callEmit() instead
+   */
   static callNext(emitter: EventEmitter<any>, value: any) { emitter.next(value); }
 
+  static callEmit(emitter: EventEmitter<any>, value: any) { emitter.emit(value); }
+
   static callError(emitter: EventEmitter<any>, error: any) { emitter.error(error); }
 
   static callComplete(emitter: EventEmitter<any>) { emitter.complete(); }
@@ -78,9 +83,9 @@ export class ObservableWrapper {
  *   toggle() {
  *     this.visible = !this.visible;
  *     if (this.visible) {
- *       this.open.next(null);
+ *       this.open.emit(null);
  *     } else {
- *       this.close.next(null);
+ *       this.close.emit(null);
  *     }
  *   }
  * }
@@ -104,6 +109,13 @@ export class EventEmitter<T> extends Subject<T> {
     this._isAsync = isAsync;
   }
 
+  emit(value: T) { super.next(value); }
+
+  /**
+   * @deprecated - use .emit(value) instead
+   */
+  next(value: any) { super.next(value); }
+
   subscribe(generatorOrNext?: any, error?: any, complete?: any): any {
     if (generatorOrNext && typeof generatorOrNext === 'object') {
       let schedulerFn = this._isAsync ?