Suggestion: 3 state 'avoid' flag for rooms

[xxxsinx]

undefined = don't avoid, but update status when vision is available
0 = don't avoid, ignore whatever horrors await
1 = avoid the room, but update status when vision is available

This would allow us to force a room to avoid=0 to allow creeps to pass through a room that's been cleared/pacified, but for which the controller is still owned by a hostile player.