Add "debug lludp packet" command to pCampbot.

This allows one to log the packets received by a particular bot that are not duplicates of already received packets.
Similar to the OpenSimulator command at the same name but currently any positive level logs all received packets.
No facility yet for logging outgoing packets.
For debug purposes.
Update libopenmetaverse to 0f4b361.

Primarily to get a small message logging improvement for pCampbot.
Add "debug lludp data out" console command for logging outgoing data just before it's put on the wire.

Unlike "debug lludp packet" which logs at the point where OpenSim first asks the clientstack to send a certain outgoing packet, this logs immediately before the actual send.
For low-level debugging purposes.