Fixed NoSuchMethodError in WorldGenGroundBush
Fixed cast issues when passing delegates to world generators, and WorldGenMegaTree method exception. This fixes BUKKIT-866, and references BUKKIT-868.

Also bumped version to 1.2.2-R0.1-SNAPSHOT to match Bukkit.
Fixed compile issues with StructureGrowDelegate not implementing the new isEmpty method
Made the auto-update-checker suggest channels to server administrators if they're upgrading past their preferred channel.
Potentially fixed crash when building at max world height
Revert filtering by dynamic block range
Implemented new 1.2 entities - this fixes BUKKIT-872 and BUKKIT-885
Fixed sending maxPlayers at initial login
World height related fixes - 128 -> 256. Addresses BUKKIT-889
Fix porting issue in World.mayPlace Fixes BUKKIT-915
Fixed hunger not behaving correctly. Addresses BUKKIT-907
Preserve data if possible when dropping Items from entities. Partial solution for BUKKIT-15
Implemented snapshot support for 1.2.
Convert contained worlds to Anvil (thanks to Amaranth)
Allow the new jungle tree type to be grown both as a single sapling and as a group of 4. Fixes BUKKIT-886
Fixed porting issue with SpawnerCreature. Fixes BUKKIT-921
Updated from 1.2.2 to 1.2.3. This fixes BUKKIT-943
Fixed porting issue in World. Now uses correct variable names to add chunks for growth. This fixes BUKKIT-934
Fixed punching out fire in creative - this fixes BUKKIT-914, thanks to md-5
Fixed chest.getInventory for double chests, thanks to Acrobot. This fixes BUKKIT-901