Return the valid max value for piston direction. Fixes BUKKIT-2191

By returning the following value (7) we remove the need to special
case pistons in any way (other than the original purpose of this
check, which is to ensure pistons have valid data)
Spigot
EMC POM changes
Revert mc version setting to 1.4.6 so 1.4.6 plugins still work
Remove CraftBukkit "Feature" of ItemStack's having infinite use.
Add 2 events for better control of mob spawning (Natural and Spawners)
Add PlayerUseItem Event so we can control when an item is consumed.
Make Items not have a repair cost increase due to Anvil usage.
Try old 1.4.5 dig speed algorithm for better results.
Load custom permissions before plugins
Entity Activation range check
Do not skip fireworks ever for ticking in loaded chunks. Thanks @mikeprimm