Instead of acting on mouse movement keys immediately in the event handler hook,
just store them, and act on them during a loop hook. This has the effect of
collecting all movement intents noticed in a full scan, and acting on them in
one go, rather than acting individually.
This makes diagonal movement (up & right keys pressed at the same time) a lot
smoother, at the cost of a few ms of delay. The delay is not noticeable, and the
smoothing would be a good trade anyway. No more jerky diagonal movements!
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>