get_icon
Description:
Gets the value set by set_icon (or if you've called set_icon_list, gets the first icon in the icon list).
Parameters:
| this | 
           a Window  | 
      
Returns:
| 
           icon for window or null if none  | 
      
Gets the value set by set_icon (or if you've called set_icon_list, gets the first icon in the icon list).
| this | 
           a Window  | 
      
| 
           icon for window or null if none  |