title: Change TabBarItem title font to bold in Swift for iOS
body: <p>I'm trying to set the font weight of a selected tab bar item to bold font. It seems as it has no effect. Any idea what is wrong. <code>forState: .Normal</code> works as expected,  <code>forState: .Selected</code> has no effect.</p>
  
  <pre><code>let tabBarItem0 = tabBar.items![0] as! UITabBarItem
  var selectedImage0 : UIImage = UIImage(named:"ic_tabbar_item_one")!.imageWithRenderingMode(UIImageRenderingMode.AlwaysOriginal)
  var fontLight:UIFont = UIFont(name: "HelveticaNeue-UltraLight", size: 12)!
  var fontBold:UIFont = UIFont(name: "HelveticaNeue-Bold", size: 12)!
  
  tabBarItem0.image = unselectedImage0
  tabBarItem0.selectedImage = selectedImage0
  tabBarItem0.title = "Overview"
  tabBarItem0.setTitleTextAttributes(
      [
          NSForegroundColorAttributeName: UIColor.whiteColor(),
          NSFontAttributeName: fontLight
      ], forState: .Normal)
  
  tabBarItem0.setTitleTextAttributes(
      [
          NSForegroundColorAttributeName: UIColor.whiteColor(),
          NSFontAttributeName: fontBold
      ], forState: UIControlState.Selected)
  </code></pre>