Because of the way lines are drawn, a specific configuration of
positioning for gormlaks would have them decide they desperately wanted
to walk *inside* a wall, which they would then both fail to do but also
always collide with whenever they tried to go anywhere else.
Add menu support to the prompt system, and an "Eat" command that prompts
for an item to eat and eats the item the character specifies, restoring
an amount of hitpoints configurable via the item raw type.
