title: How can I change the NavBar title text color in swift 4?
body: <p>When developing in swift 3 I was used to write:</p>
  
  <pre><code>UINavigationBar.appearance().titleTextAttributes = [NSForegroundColorAttributeName: UIColor.orange]
  </code></pre>
  
  <p>putting this in AppDelegate would change all the UINavbars' title color to orange.</p>
  
  <p>Now I want to do the same with Swift 4 and iOS 11. </p>