Make crystal devices work saner and more intuitive

Make crystal devices work saner and more intuitive

Crystal devices now leave alone the crystals already in the room.

Before this, all crystals (including those in the player room) were randomly
spawned in the player room. This appeared as if these crystals were gone for
good and may be confusing for some players. The message pop-up is now also
updated accordingly; if there are no crystals in *other* rooms, the message
now correctly states that the crystal device “does not work” (=would have
no effect).