This adds touch gestures to the touchpad-style mouse
controls. Before this, there was only pointer motion
via dragging a finger somewhere on the screen. Now,
there's tap to click and more.
Supported touch gestures:
- pointer motion = single finger drag
- left mouse click = single finger short tap
- right mouse click = second finger short tap
while first finger is still down
- left click drag and drop = dual finger drag
- right click drag and drop = triple finger drag