Fix bugs with kills while killer is offline (firewall). Prevent monsters from hitting other monsters they can't reach (i.e. Kriipa and groundworms).

Currently the killer's room is always used to determine whether they receive a penalty or not. There are cases where the killer will be offline or out of the room (firewall, minions) when the kill occurs, so the victim's room should really be used (guaranteed to be at the killed location, and online).

Put a sanity check in the DropTimer message in kriipa.kod to prevent errors with $ owner.

Also stopped monsters hitting other monsters if CanMonsterFight returns false; this occurs with Kriipa on ceilings and groundworms in the ground.