title: Set image and title for bar button item?
body: <p>I currently have a custom navigation controller with bar button items that are simply text buttons. Is it possible to keep the title of the bar button items but also set them as images (icon image + title underneath).</p>
  
  <pre><code>class NavigationController: UINavigationController
  {
      var mode: NavigationMode = .Swipe {
          didSet {
              self.setButtonAttributes()
          }
      }
  
      private var leftBarButton: UIBarButtonItem!
      private var middleBarButton: UIBarButtonItem!
      private var rightBarButton: UIBarButtonItem!
      private var rightBarButton2: UIBarButtonItem!
  
      override func viewDidLoad()
      {
          super.viewDidLoad()
      }
  
      func configureNavigationItem(navigationItem: UINavigationItem)
      {
          //Configure the bar buttons text and actions
  
  
          if (self.leftBarButton == nil) {
              self.leftBarButton = UIBarButtonItem(title: "Menu1", style: .Plain,target: self, action: "menu1Pressed:")
          }
          if (self.middleBarButton == nil) {
              self.middleBarButton = UIBarButtonItem(title: "Games", style: .Plain, target: self, action: "gamesPressed:")
          }
          if (self.rightBarButton == nil) {
              self.rightBarButton = UIBarButtonItem(title: "Menu3", style: .Plain, target: self, action: "menu3Pressed:")
          }
          if (self.rightBarButton2 == nil) {
              self.rightBarButton2 = UIBarButtonItem(title: "Settings", style: .Plain, target: self, action: "settingsPressed:")
          }
  
          self.setButtonAttributes()
  
          navigationItem.leftBarButtonItems = [self.leftBarButton, self.middleBarButton, self.rightBarButton, self.rightBarButton2]
  
      }
  </code></pre>
  
  <p>Updated:</p>
  
  <pre><code>  let button = UIButton(type: .System)
          button.setImage(UIImage(named: "play"), forState: .Normal)
          button.setTitle("Play", forState: .Normal)
          button.sizeToFit()
  
          leftBarButton = UIBarButtonItem(customView: button)
  
          if (self.leftBarButton == nil) {
              self.leftBarButton = UIBarButtonItem(title: "Play", style: .Plain,target: self, action: "Pressed:")
          }
  </code></pre>