Added negative id check to Material.getMaterial(int). Fixes BUKKIT-3414
Negative id values would try to access the array out of bounds and throw an java.lang.ArrayIndexOutOfBoundsException.
Update Bukkit to Minecraft 1.4.7
Updated version to 1.4.7-R0.1 in pom.xml for Beta.
Updated version to 1.4.7-R0.2-SNAPSHOT for development towards next release.
[Bleeding] Add experimental support for entity portal traveling

EntityPortalEvent is called when an entity is about to portal to a
new location. This event is cancellable on top of being able to
change the exit location.

EntityPortalExitEvent is called when exiting the portal, allowing
for adjustment of the exit velocity.