API! \o/

Implementing ICarpentersHammer or ICarpentersChisel into an item allows
you to have support for rotating / changing the blocks and chisel stuff.

Also got 2 methods: onHammerUse / onChiselUse (adding damage to the
hammer / chisel)
and
canUseHammer / canUseChisel (self-explanary)

Also removed unnecessary imports *cough* :P