LR Dynamic Dungeon Fixes

1.1

• Look at a lock block (the door before a treasure or boss room): the mobs of that room that are still alive glow, and the action bar shows "Mobs left to kill: N". Both can be turned off in the config (lock-highlight, lock-actionbar-counter).
• After the last mob of a room is dead, players near the room get the message "Room is cleared, the exit is now open." (option room-cleared-message).