get_rowstride
Description:
Get the number of bytes per line of the framebuffer
Parameters:
| this | 
           the framebuffer object  | 
      
Returns:
| 
           the framebuffer row stride  | 
      
Get the number of bytes per line of the framebuffer
| this | 
           the framebuffer object  | 
      
| 
           the framebuffer row stride  |