public void Remove(Controller controller)
 {
     PlayerController playerController = controller as PlayerController;
     if (playerController != null)
         this.PlayerControllers.Remove(playerController);
     else
         controllers.Remove(controller);
 }
 public void Add(Controller controller)
 {
     PlayerController playerController = controller as PlayerController;
     if (playerController != null)
         this.PlayerControllers.Add(playerController);
     else
         controllers.Add(controller);
 }