/// <summary>
 /// Unground the player
 /// </summary>
 /// <param name="velocity">The velocity at which the player has been ungrounded</param>
 public void Unground(double velocity)
 {
     if (Gravity == null)
     {
         Gravity = new GravityArgs(Bottom, velocity);
     }
 }
 /// <summary>
 /// Ground the player
 /// </summary>
 public void Ground()
 {
     Gravity = null;
 }