MonoGame 3.5.1中Mouse.GetState()存在BUG，获取的坐标点始终是0，可以用TouchPanel暂时解决

MonoGame 3.5.1 Mouse.GetState()存在Bug，获取的坐标点始终是0.在官方修复之前可以用TouchPanel暂时解决。当然只在iOS，android，WP，UWP等带触摸屏幕的设备上有效。UWP例外

var touches = TouchPanel.GetState(); 
            if (touches.Count > 0) 
            { 
                ms = new MouseState((int)touches[0].Position.X, (int)touches[0].Position.Y, 0, ButtonState.Pressed, ButtonState.Released, ButtonState.Released, ButtonState.Released, ButtonState.Released); 
            } 
            else 
            { 
                ms = Mouse.GetState(); 
            }