+Tweaked challenge items to account for Repentance changes
+Added special Suplex interaction

Fixed Mahalath being able to replace Mom on XL floors.

removed some leftover ui files that interfered with the stain's boss portrait

blame deadinfinity

fixed pieces of c.h.a.d. being replaced with mahalath

reduced mahalath's health in new challenge from 500 to 450
batteries in new challenge will now disappear after a few seconds

deleted unused files

forced DeadInfinity to add his artifical boss pool code to Mahalath and make a couple minor bug fixes
mahalath now has a chance to replace Depths bosses
probably fixed whatever changed recently to break Delirium
added a second challenge

fixed bug causing no trap door to spawn after some fights, made basic mahalath a little easier (longer pauses between some attacks), prevented champion tints from applying, added another (?) secret fight to the challenge

enabled mahalath-stain replacement under all circumstances instead of just boss rooms, disabled mahalath spawning mouth and switching to second form during delirium fight (for many reasons)

fixed projectile firing bug caused by new update, lowered mahalath health, enlarged mahalath hitbox, added graphical tweaks