get_touch_only
Description:
Returns true if the gesture is only triggered by touch events.
Parameters:
| this | 
           a `GtkGestureSingle`  | 
      
Returns:
| 
           true if the gesture only handles touch events  | 
      
Returns true if the gesture is only triggered by touch events.
| this | 
           a `GtkGestureSingle`  | 
      
| 
           true if the gesture only handles touch events  |