Workaround strange behaviour in the Minecraft XP system

There are various methods which can be used to get a players XP each of which seems to work of its own data and these different "views" are not always synchronised which can lead to a players XP being incorrectly set when their state is restored.

This change uses a set of methods which workaround this issue and resolve the known glitch when players can duplicate their XP straight after enchanting.
Add missing changes for fill region, add config option to allow team messaging to be disabled in an arena and remove some debug.