Fix crabpony bug, remove mutex logs

Fix bug where a retransmission would still be processed.

Remove logs of mutexes locking/unlocking since it seems stable (no deadlock yet).
Fix login server bug and add less log

Fix bug where the login server would create new empty players in player.dat

Remove log when broadcasting animations (fly / dance / sit / ...)
BTW: We have animation support since the last commit.
Some errors aren't status messages anymore.

Errors when sending a message aren't status messages anymore, as long as we manage to restart the UDP server.
Add a descriptive error message when we failed to send a message.

Sending a save to a netview ID that doesn't exist isn't a status message anymore. We just ignore the missing player.
Save players on exit, fix log

Save players when the server exits.
Remove some useless and CPU heavy messages from the log
Bump version number to 0.4.1
Start implementing skills

Also fix casting bug receiveMessage that could crash the server.
Add spells support (NOT teleport)

There is no checking, the server accepts all spells blindly.
Teleport in particular always works, but you'll land in a random place.
Fix potential PNet bugs.

Always cast everything that comes from the network to quint8. Always.
I had forgotten to cast some bytes, and they could have overflowed.
merge