ISpecialBow may determine nocking behavior

This is only for visual purposes, signalling the player that the current bow + arrow/quiver/inventory setup will not allow them to fire, thus saving them from wasting time pulling the bow - much like the vanilla bow when an arrow is not found in the inventory.
Hook for ISpecialBow custom fire handlers
Merge pull request #110 from coolAlias/master

Hooks for ISpecialBow