[implemented] Parent/Child Furniture Relationships (aka: Chip! Holy ---- this rocks)

[Cardinal05]

Originally Posted by sirinsidiator I'll also need this to update SaveHouse so it saves and restores the groups. If the message rate limit is too low, it will take forever to restore a saved state in a house with many groups.

Also, just to add, from what I have found and what I program for:

- The limit is 10 item placements, removals and moves per second.

- The limit for changing item state seems to be drastically lower -- I have to throttle it down to 2 state changes per second. I'm not sure why (perhaps more calls are being done on our behalf under the hood?).

- The limit for unlinking (and possibly linking) items is so low right now that I gave up on trying to use it because I was repeatedly kicked from the server. I think it may be, in part, due to O(n) calls being done on our behalf under the hood where n is related to the number of children; but I can't be certain.