message: Convert cout debug message to exception in UIContainer
diff: @@ -60,8 +60,7 @@ void UIContainer::bringToFront(Control* control)
  auto control_iterator = std::find(mControls.begin(), mControls.end(), control);
  if (control_iterator == mControls.end())
  {
  - std::cout << "UIContainer::bringToFront(): Control is not managed by this container." << std::endl; // debug aid, can be pulled in release modes.
  - return;
  + throw std::runtime_error("UIContainer::bringToFront(): Control is not managed by this container.");
  }
  mControls.back()->hasFocus(false);
  