Called when the mouse is not any longer over the GUIElement or Collider.
A call to OnMouseExit follows the corresponding calls to OnMouseEnter and OnMouseOver.
This function is not called on objects that belong to Ignore Raycast layer.
You can use OnMouseExit as a co-routine if you add a yield statement somewhere in the function.
This event is sent to all scripts attached to the Collider or GUIElement.