title: Property 'interval' does not exist on type 'Observable<any>'
body: <p>I have the following code inside the constructor of my Angular2 component class:</p>
  
  <pre><code>Observable.from([1,2,3]).interval(2000).subscribe(e=&gt;{
           console.log(e);
         });
  </code></pre>
  
  <p>I imported the following:</p>
  
  <pre><code>import { Observable } from 'rxjs/Observable';
  import 'rxjs/add/observable/from';
  import 'rxjs/add/observable/interval';
  </code></pre>
  
  <p>I have the following error message while building my project using Angulat CLI:</p>
  
  <pre><code>Property 'interval' does not exist on type 'Observable&lt;any&gt;
  </code></pre>
  
  <p>What am I missing?</p>