Abstract class that every gesture should implement to evaluate some core function
 /// <summary>
 /// to add a new gesture to the list.
 /// </summary>
 /// <param name="g">the gesture to be added</param>
 public void AddGesture(Gesture g)
 {
     gestures.Add(g);
 }
 public void AddGesture(Gesture g)
 {
     gestures.Add(g);
 }