Don't "setLastDamageCause" in the DamageEvent constructor. Addresses BUKKIT-1881

This is now done after the event to allow you to be able to get previous damageCauses, and is now only applied if the event is not canceled.
Implement server.getMotd() for BUKKIT-1799
Add API to get a players experience to level (getExpToLevel). Implements BUKKIT-1906

This is the total experience one needs to gain a level.
Updated version to 1.2.5-R5.0 in pom.xml for RB.
Updated version to 1.2.5-R5.1-SNAPSHOT for development towards next release.
Update Bukkit for 1.3.1 changes
Add LargeBiomes WorldType.
Revive the toggledownfall permission! (and fix descriptions)
Test command permissions before running them.
Warn server owners of plugins using deprecated events. Fixes BUKKIT-2027
BREAKING: replace defunct PlayerChatEvent with async chat. Addresses BUKKIT-2064

PlayerChatEvent is now Deprecated. It should be fired asynchronously, but
has not been so traditionally. To do so would massively break plugins that
rely on it.

AsyncPlayerChatEvent now replaces PlayerChatEvent. It uses comparable
functionality, but can be fired without synchronizing to the event manager.
The event will sometimes fire synchronously if triggered by a plugin.

Because PlayerChatEvent is now deprecated, PlayerCommandPreprocessEvent will
no longer extend PlayerChatEvent. This is almost completely source and
binary compatible, bar plugins that downcast to PlayerChatEvent.
Additionally, some methods that are non-functional have been marked
deprecated and indicate such.

Additionally, new constructors are now provided to allow for lazier
initialization of the receiving player set. A note has been added stating
plugins should be prepared for UnsupportedOperationExceptions if the caller
provides an unmodifiable collection.
[Bleeding] Add new MaterialData classes for new blocks and update existing blocks with new data
Change inheritance for new MaterialData.
Fail silently on incorrect number input
Update commands to match 1.3 vanilla commands
Don't send duplicate messages for Gamemode and Time commands.

Gamemode gets sent with the packet.
Add Warning API and settings for Deprecated events
Purge outdated biomes. Fixes BUKKIT-1087
Updated version to 1.3.1-R1.0 in pom.xml for RB
Updated version to 1.3.1-R1.1-SNAPSHOT for development towards next release.