title: Navigation Bar not showing color and bar button item on adding MMDrawerController
body: <p>I have added <code>MMDrawerController</code> to my project,before using <code>MMDrawerController</code> the navigation bar was appearing as desired in black color and the bar button item was also visible but when I added <code>MMDrawerController</code> to the project ,the navigation bar shows grey color rather than showing black and the bar button item also doesn't come .Kindly help me to get the navigation bar in black color and bar button item also visible.Thanks in advance!</p>
  
  <p><a href="https://i.stack.imgur.com/gC5Mb.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gC5Mb.png" alt="navigation bar settings"></a></p>
  
  <p><a href="https://i.stack.imgur.com/Q3pWX.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Q3pWX.png" alt="output on simulator"></a></p>
  
  <p>//MARK: function for adding MMDrawer controller
   func buildNavigationDrawerInterface () {</p>
  
  <pre><code>    let mainStoryBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
      let centerVC = mainStoryBoard.instantiateViewController(withIdentifier: "tabbar") as!UITabBarController
  
      centerVC.tabBar.barTintColor = UIColor.black
      let leftVCs = mainStoryBoard.instantiateViewController(withIdentifier: "LeftViewController") as! LeftViewController
  
  
      let leftSideNav =  UINavigationController(rootViewController: leftVCs)
  
      let centerSideNav = UINavigationController(rootViewController: centerVC)
  
      drawerContainer = MMDrawerController(center: centerSideNav, leftDrawerViewController: leftSideNav)
  
      drawerContainer!.openDrawerGestureModeMask = MMOpenDrawerGestureMode.panningCenterView
      drawerContainer!.closeDrawerGestureModeMask = MMCloseDrawerGestureMode.panningCenterView
      //centerContainer?.setDrawerVisualStateBlock(MMDrawerVisualState.swingingDoorVisualStateBlock())
  
      window!.rootViewController = drawerContainer
      window!.makeKeyAndVisible()
              }
  </code></pre>