Fix spacepod weapons

Created by: Exxion

Fixes #3293 (closed), along with a few various issues with spacepod weapons. First and most obviously, spacepod weapons... work. Removing a weapon from a spacepod also now actually removes the fire verb.

The only change not directly related to spacepods is to the dumbfire proc of beam projectiles. For whatever reason, it had an argument for direction, but ignored it in favor of just finding src.dir and using that instead. Now it uses the dir argument if provided, but uses src.dir otherwise. (Spacepod lasers would fire from the right places but exclusively southward without this change due to ridiculous src fuckery. And yes, the spacepod would shoot itself if facing any other direction.) I'm not sure if that affects anything other than spacepods anyway, but I might as well list it.