public void DeregisterUpdateableObject(IUpdateableObject obj)
 {
     if (_updateableObjects.Contains(obj))
     {
         _updateableObjects.Remove(obj);
     }
 }
 public void RegisterUpdateableObject(IUpdateableObject obj)
 {
     if (!_updateableObjects.Contains(obj))
     {
         _updateableObjects.Add(obj);
     }
 }