1) Don't put two pits in the same room.
2) Don't put bats and pits in the same room. (you will never hit the bat)
3) Don't start the player in a room with a pit or bad, if possible. Some
caves are so crowded the loop may go on forever, so we give up after 100
tries to put them in a safe location (as long as it's not with the wumpus).
4) Make the manpage reflect reality WRT the default number of rooms.
Bug #3 pointed out by salo.
