BUGFIX & CONTENT: Love for the auxiliary weapons - fixes underbarrel weapons unloading bug and adds new weapons.

I discovered a bug in the course of creating this stuff. Previously, a lot of the underbarrel weapons couldn't be unloaded. Once ammo went in, it was either fired to clear it, or else it stayed there FOREVER. This fixes that.

In addition it also includes new weapons:

40mm signal flare rounds.
New underbarrel caseless shotgun.
Three new standalone near-futuristic caseless shotguns
New caseless shotgun ammunition and subtypes.
Spawns and supporting stuff.