title: How to properly handle a nil UIApplication.sharedApplication().keyWindow
body: <p>When the <code>viewDidLoad</code> is called the view is supposed to be loaded.</p>
  
  <p>But I always crash in <code>UIApplication.sharedApplication().keyWindow</code> being nil... </p>
  
  <p>Where should I put my code to have it called once the view is loaded and not everytime the user comes back (I have excluded viewWillAppear for that reason) ? </p>