Bukkit

Changes:
+ Added GUI for adding particles, changing the ground etc.
+ Added /bg setfloor <arena> <place>
+ Added /bg reload
* Fixed timer not displaying first time
* Fixed error on leaving
* Fixed gamemode not changing
* Inventory not getting cleared when joining an arena
* Fixed being able to lose health and hunger in the game
Due to a bug in Minecraft, when using BarAPI you can see the enderdragon.