Lots of fixes...

-Fixed a bunch of desolatorXT's absolutely RETARDED code on buffs and
movement... In fact, I left some of the old movement code in (commented
out) for comparison and shameful humiliation.
-Added a movement speed pickup/buff/aura.
-Added a separate game-over menu (not sure about this), to add a
"restart" option. It works but it needs a sprite. Do it.
-Look at the TODO file, I've noted some issues there.