title: Set title (color/font)of UINavigation controller at the same time (strange behaviour)
body: <p>I'm getting some strange behaviour when i'm trying to customize the look of the UINavigation controller in the app delegate.</p>
  
  <pre><code>UINavigationBar.appearance().titleTextAttributes = [NSFontAttributeName: UIFont(name: "Avenir Next", size: 20)!]
  
  UINavigationBar.appearance().titleTextAttributes = [NSForegroundColorAttributeName: UIColor(red: 93/255, green: 173/255, blue: 173/255, alpha: 1)]
  </code></pre>
  
  <p>Whenever I set the color first the font doesn't change, and when i set the font first, the color and the font don't change. However If I set the fond on its own then it changes... I can't seem to do both at the same time. Is there another way i'm supposed to be doing this.</p>