generalized parallax code and added factory bg
map border

added nasty tile that we use to border maps preventing ray traces out of
map. remember to replace with transparent tile before shipping!
sewer map more pretty
added performance hack for GlobalEntityList
added placeholder music for each level
GameInput has extra support for hidden buttons

these will be used for cheat codes
added locked levels and cheat code

hold left bumper and press X on title screen to unlock further levels
added level time records
added tagline when levels start
title screen "BEGIN" option now loads first level
updated tutorial, flagdoors, and sfx
particle div/zero fix
modified flagkey + tutorial locations