title: UIStatusBarStyleLightContent for MFMailComposeViewController
body: <p>Can you please suggest me, what is the proper way to setup the style of statusbar for <code>MFMailComposeViewController</code> in iOS >= 9.0?
  I know, that <code>[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];</code> is deprecated and I can't use it.
  I know that the possible solution is adding category like this:</p>
  
  <pre><code>#import "MFMailComposeViewController+StatusBarStyle.h"
  @implementation MFMailComposeViewController (StatusBarStyle)
  #pragma mark - Status bar management
  - (UIStatusBarStyle)preferredStatusBarStyle {
      return UIStatusBarStyleLightContent;
  }
  - (UIViewController *)childViewControllerForStatusBarStyle {
      return nil;
  }
  @end
  </code></pre>
  
  <p>But in this case I should enable <code>View controller-based status bar appearance</code> option and implement <code>- (UIStatusBarStyle)preferredStatusBarStyle</code> in the all ViewContollers that exist in my app (and I have a lot of them).
  So, is there another solution?</p>