0.1.5c

More bug fixes, and bringing Linux+Mac versions up-to-date.

Fixes
	Crash when wraiths have no target
	Player is annihilated upon entering a floor in a snowdrift
	Humanoids trying to chase through locked doors constantly jiggle the doorknob loudly
	AI_action_backhop crash
	Energy bar looks weird when you changing to equipment with less MAG
	Regeneration overwrites owl wings when flying
	Ceiling spikes draw beneath jump-thru platforms in the AC
	Lava bridges are now destroyed when lava loses it heat (Reaper fight, siphon, etc)
	Pressing select+cancel at the same time over a gravestone select backs to class select but still shows the custom kid dialog
	Backing out of kid select shows particles for destroyed mana batteries
	Shopkeepers get mad at you if you're infected with any plague flies
	Pressing select+cancel at the same time on the level-up screen levels the selected stat without advancing its tier
	Flame cone traps shoot at the wrong angle
	Crash when going through the tank door in co-op