Improved Auto Crossbow

Good news! Through idle musings on how to improve existing weapons I have come up with a way to make the auto-crossbow fully automatic.

The method was relatively simple. The push from the feeder itself can be used to ratchet the string back into the firing position after a shot. This only required a small change in design, feeding the arrows in from the bottom instead of the side, but I think this is overall for the better.

I also added a second feeder, for weight balance, effectively doubling the arrow capacity.