Prevent mp items from spawning on skills 5 and 6.
Disable store on skills 5 and 6.
Fix Shotgunners dropping Wallbusters in Doom 1.
Fix episode/skill menus being compacted when they have more than 5 text items.
Tweak message boxes.
A bunch of silly tweaks to player movement, including bunnyhop acceleration.
Readjust math for top speed stat unit conversion.
Add two more future achievements.
