Filter mob spawns by depth and biome
Use mob data to stat mob spawns
Enemy mobs spawn asleep, statuses & intrinsics work
Comment update
FOV API for seen location iteration
Status flag set API
Mobs wake up when player is nearby, fov in world system
Enemies now home in and attack player

Removed grid bugs, the weird movement logic started infecting all AI
and pathfinding code, and the bugs aren't interesting enough a
feature to warrant all the extra code mass.