title: UIStatusBarStyle PreferredStatusBarStyle does not work on iOS 7
body: <p>In my iPhone application built with Xcode 5 for iOS 7 I set <code>UIViewControllerBasedStatusBarAppearance=YES</code> in <code>info.plist</code>, and in my <code>ViewController</code> I have this code:</p>
  
  <pre><code>-(UIStatusBarStyle) preferredStatusBarStyle
  {
      return UIStatusBarStyleLightContent;
  }
  </code></pre>
  
  <p>But the status bar is still black against the black background. </p>
  
  <p>I know its possible to change this app-wide by setting <code>UIViewControllerBasedStatusBarAppearance=NO</code> in <code>info.plist</code>, but I actually need to alter this on a <code>viewController</code> by <code>viewController</code> basis at runtime.</p>