[DON'T MERGE] Improvised shotguns

- Made from wood stacks and a hacked (and upgraded) autolathe as well as cable coil.
- Essentially a double barreled shotgun with a single barrel(only shoots one shell at a time).
- Scientists can now actually use tech shells if they put forth the effort to make these ghetto shotguns.
- Trying to open crates with this to do guncargo takes a fucking long time (>15m) so guncargo shouldn't be an issue
- VIVA!

This requires additional testing but while I do said testing I'd like to make tweaks based on feedback on the code and construction process. A lot of this is pretty modular as well.
__Suggestion__

Add a _set_icon()_ function for both class :
```icon_state = "isawnshotgun"```
for the parent
``` icon_state = "sawnshotgun"```
for the child

and call it instead of the istype().