title: Attach view only after all composed modules are activated in DurandalJS.
body: <p>I have a main view with two sub-views (using DurandalJS composition). Right now, the main view's viewAttached event is firing early while my sub-views are still dealing with ajax requests. Ideally, the main view would only attach the view to the DOM and run the transition AFTER all composed sub-views have finished activating. </p>
  
  <pre><code>&lt;h1&gt;Hello World&lt;/h1&gt;    
  &lt;div data-bind="compose: { model: 'viewmodels/subview1', activate: true }"&gt;Loading...&lt;/div&gt;    
  &lt;div data-bind="compose: { model: 'viewmodels/subview2', activate: true }"&gt;Loading...&lt;/div&gt;
  </code></pre>