sleeping monsters, noise, caching actor rooms

monsters being not awake, basic noise model (1d6 + extranoise -
2*roomdistance > 1), caching which actors are in which rooms
(dict<actor, room> and dict<room, actor>) (calced when someone moves, in
future, maybe check whether actor actually changed room. we are
turnbased, so ok for now), caching which rooms are linked (sharing
atleast one tile)