0.3.1 Hotfix #18

Fixed a bug where Gambler items had no cost
Fixed a bug where item cost at the Gambler was calculated incorrectly while selling. The item's base price is now factored in. This is a buff
Fixed a bug where the Gambler would charge you Nightmare Essence for Gambled Nightmare items. This was illegal!
Fixed a level generation issue with the Maintenance Corridor tileset
Made some underlying item model and framework changes to support an upcoming content patch