set_margin_top
Description:
Sets the margin from the top of a Actor.
The margin_top property is animatable.
Parameters:
| this | 
           a Actor  | 
      
| margin | 
           the top margin  | 
      
Sets the margin from the top of a Actor.
The margin_top property is animatable.
| this | 
           a Actor  | 
      
| margin | 
           the top margin  |