title: Call WKInterfaceController's method from UIViewController
body: <p>I have an iPhone app and added a WatchExtension. Now I managed to send a string to the Watch using the <code>MMWormhole</code>. In order to use the string I must call <code>update()</code> inside the <code>WKInterfaceController</code> from a method inside my <code>UIViewController</code>, so the iPhone application. <br>
  Is that possible?</p>
  
  <p>I tried to do something like <code>InterfaceController.update()</code> but Xcode complained that it does not know the variable <code>InterfaceController</code>.</p>
  
  <p>Thanks in advance :)</p>