rotate
Description:
Rotates the item's coordinate system by the given amount, about the given origin.
Parameters:
| this | 
           an item.  | 
      
| degrees | 
           the clockwise angle of rotation.  | 
      
| cx | 
           the x coordinate of the origin of the rotation.  | 
      
| cy | 
           the y coordinate of the origin of the rotation.  |