Creatures now receive health when they pick up a health pack.
Moved the rendering code to a separate Renderer-class.
Commands can now add log messages to the arena to let viewers know what is happening.
Health packs now cannot spawn on top of creatures or other health packs.
Added weapons to the arena.
Generalized items (health packs, weapons) and spawners.
Generalized picking up of items.
Made Arena.IsOccupied more efficient.
Added armor.
Creatures now receive a list of enemies that are near.
Creatures now receive lists of items that are near.
A creature can now hit another creature, even though it doesn't do any damage.