title: What does `TypeError: core_2.EventEmitter is not a function` actually mean?
body: <p>Trying to implement output emitter here:</p>
  
  <pre><code>import {Component} from 'angular2/core';
  import {EventEmitter} from "angular2/core";
  import {steps} from "../wizard/steps";
  
  @Component({
    selector: 'wizard-step-1',
    outputs: ['suggestStep'],
    templateUrl: 'app/components/wizard-step-1/wizard-step-1.html',
    styleUrls: ['app/components/wizard-step-1/wizard-step-1.css']
  })
  export class WizardStep1 {
    suggestStep = new EventEmitter();
    constructor() {}
    proceed () {
      this.suggestStep.emit(1);
    }
  }
  </code></pre>
  
  <p>That one works. However, when i try passing an enumerable to the <code>.emit(enum)</code> like this:</p>
  
  <pre><code>this.suggestStep.emit(steps.step2);
  </code></pre>
  
  <p>Browser fails with:</p>
  
  <pre><code>EXCEPTION: EXCEPTION: Error during instantiation of WizardStep1!.
  ORIGINAL EXCEPTION: TypeError: core_2.EventEmitter is not a function
  ORIGINAL STACKTRACE:
  TypeError: core_2.EventEmitter is not a function
      at new WizardStep1 (http://localhost:4200/app/components/wizard-step-1/wizard-step-1.js:27:40)
      at http://localhost:4200/vendor/angular2/bundles/angular2.dev.js:1372:20
      at Injector._instantiate (http://localhost:4200/vendor/angular2/bundles/angular2.dev.js:11917:19)
      at Injector._instantiateProvider (http://localhost:4200/vendor/angular2/bundles/angular2.dev.js:11859:21)
      at Injector._new (http://localhost:4200/vendor/angular2/bundles/angular2.dev.js:11849:19)
      at InjectorInlineStrategy.instantiateProvider (http://localhost:4200/vendor/angular2/bundles/angular2.dev.js:11609:28)
      at ElementInjectorInlineStrategy.hydrate (http://localhost:4200/vendor/angular2/bundles/angular2.dev.js:13234:20)
      at ElementInjector.hydrate (http://localhost:4200/vendor/angular2/bundles/angular2.dev.js:12882:22)
      at AppViewManagerUtils._hydrateView (http://localhost:4200/vendor/angular2/bundles/angular2.dev.js:9662:31)
      at AppViewManagerUtils.hydrateViewInContainer (http://localhost:4200/vendor/angular2/bundles/angular2.dev.js:9638:12)
  ERROR CONTEXT:
  [object Object] in [steps.step1 in Wizard@4:3]
  </code></pre>
  
  <p>I don't see the connection between the change and the error. Do you?</p>