Add support for mouses using the GameController framework. This requires
iOS 14 and up. The trackpad on the magic keyboard to iPads is connected
as a mouse and of course other connected mouses.
The mouse movements triggers calls to the mouseMovedHandler code
block. The calls delivers delta movements on the X and Y axis from the
last pointer position. It doesn't keep track on where the pointer is in
the view. That's where pointerPosition property in the iPhoneView comes
into place.
