* Add Netherrack slabs and walls
Also adds deep netherrack stairs, and deep nether brick stairs, slabs, inner stairs and outer stairs.
Adds 9 new nodes in total.
* Treasure: Nether pickaxe takes 10x less wear damage when mining netherrack
cracky-3 mining time of Nether pickaxe reduced from 0.4 to 0.3 to mine netherrack faster.
maxlevel of nether pickaxe dropped from 3 to 2 to increase wear damage with non-netherrack nodes.
* Treasure: Nether staff of light
Adds "Nether staff of Light" and "Nether staff of Eternal Light"
One is limited to 60 uses, and the other has unlimited uses but the glowstone it creates will only last for 40 seconds.
There are no crafting recipes as I hope these to eventually be treasure that can be found in the nether.
See the pull request (#50) for more discussion
Treer