Bugfix: Monsters that manage to level up no longer end up with NaN health and energy.
Tweak: Add special messages for objects and thieves having full inventory (thieves randomly drop something)
Bugfix: Altars would sometimes drop items in a wall.
Bugfix: An error was raised if a blink hound could no longer see you.
Bugfix: When sacrificing food, two references to the reward were dropped on the floor, allowing it to be picked up infinitely.
Tweak: Altars now consider nourishing potion to be food.
A more general fix for entities being double-referenced in lists; now the list will simply not add an entity if it's already there.
(It's not 100% foolproof, but hopefully it'll catch any other similar issues.)