Xenoarch fixes [merge okay]

- Energy guns should now spawn with the proper sprite, as well as keep that sprite on charging
- No more runtimes from access len on a null list
- Changed some relative pathing
- Fixed something that would cause type errors in calibers
- Should fix #1699

I have to do more testing on war sites, but the icon problem should be fixed.
Xenoarch is hard to test.

EDIT: Did some testing, everything works just fine.
Guns now spawn with the icons and charging them lets them keep the icon.