Crossbow bolts stackable

I've made the crossbow bolts stackable (quiver like functionality). Currently it's limited to 1 quiver (4 bolts). I had to use some hackish ways to do this because the engine is lacking the proper functions.

Bolts looted from lootspots and zombies are first put in gear as a normal bolt. Once you close the gear dialog it will be removed and a bolt will be added to the quiver (this is where the engine is lacking at the moment). Bolts fired from the crossbow can be picked up and will instantly be added to the quiver. After a bolt has been fired you will have to reload a bolt so it won't act like a rifle.

Tested and working, should be bug free.