title: Observable forkjoin subscribe types
body: <p>I'm making 2 API requests calls with typed responses, combining them into a single <code>Observable.forkJoin</code>. I want to get both results in different typed variables.</p>
  
  <pre><code>var observableOrganization: Observable&lt;Organization&gt; = this.getOrganizationDetails();
  var observablePromotion: Observable&lt;Promotion[]&gt; = this.getPromotions();
  
  Observable.forkJoin([ observableOrganization, observablePromotion])
      .subscribe(
          response =&gt; {
              organization: Organization = response[0];
              promotions: Promotion[] = response[1];
          },
          error =&gt; {
              // ...
          }
      );
  </code></pre>
  
  <p>How can I reach typed results in single subscribe response?</p>