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Purge outdated biomes.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.
Add spaces to gamemode message. Fixes BUKKIT-2148
Add API for getting and setting experience for BlockBreakEvent. Addresses BUKKIT-2033
Change Player usage in unit tests to proxies
Add API to set and get movement modifiers. Addresses BUKKIT-2205
Add interface for spawning FallingBlocks and correctly spawn a FallingBlock with the spawn(Location, FallingBlock.class) method. Adds BUKKIT-2282

Also add FallingBlock and methods.

Deprecated FallingSand to emphasize FallingBlock.
Let TripwireHook be attachable. Addresses BUKKIT-2278

This commit also makes TripwireHook consistent with other attachables
for the facing property.
Fully restrict the org.bukkit and net.minecraft namespace
Add isChunkInUse() to World. Addresses BUKKIT-2330
Updated version to 1.3.1-R2.0 in pom.xml for RB.
Updated version to 1.3.1-R2.1-SNAPSHOT for development towards next release.