title: revealViewController() always returns nil
body: <p>I'm having some troubles with <code>revealViewController</code> in Xcode 7.2 and iOS 9.2.</p>
  
  <p>My app starts with a view controller embedded in a navigation controller to perform a login.
  After login, or if the login token is present, I jump to another view controller embedded in a navigation controller with the following code:</p>
  
  <pre><code>let homePage = self.storyboard?.instantiateViewControllerWithIdentifier("HomeViewController") as! HomeViewController
  let homePageNav = UINavigationController(rootViewController: homePage)
  let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
  appDelegate.window?.rootViewController = homePageNav
  </code></pre>
  
  <p>In this home view controller I would like to have a left navigation menu with <code>SWRealViewController</code>.</p>
  
  <p>I had the <code>SWRealViewController</code> view linked with <code>sw_front</code> to my home navigation controller, and the following code:</p>
  
  <pre><code>if (self.revealViewController() != nil) {
      self.menuButton.target = self.revealViewController()
      self.menuButton.action = "revealToggle:"
  self.view.addGestureRecognizer(self.revealViewController().panGestureRecognizer())
  </code></pre>
  
  <p>But <code>self.revealViewController()</code> always returns nil, so it does not work.</p>
  
  <p>I think I lost the <code>revealViewController</code> somewhere (maybe when I jump from the first navigation controller to the second) but I do not know what to do.</p>