Fixes #80, fixes #355, fixes #258

#80 is fixed by removing the vanilla recipes for stairs and slabs
#355 is fixed by using setBlockToAir instead of setBlock to 0
#258 is fixed by instead of using the zombie attackEntityFrom(DamageSource par1DamageSource, float par2) which would spawn vanilla zombies to use the EntityLivingBase attackEntityFrom(DamageSource par1DamageSource, float par2)

Sorry for the twice "logomaster256 referenced this issue from a commit in logomaster256/TFCraft" I noticed that I didn't remove slabs so I did that and squashed and ^ happened