[WIP] Syndicate Operative additions

http://tgstation13.org/phpBB/viewtopic.php?f=14&t=205

- Changes the Stechkin silencer to a 'universal' syndicate silencer for all small arms. This currently only includes the Stech and C20r SMG.
- Adds the 30-round spess AK, a less clunky but lower ammo 7.62 rifle, manufacturing title "CB-47"
- Adds the mag-fed semi-automatic syndicate operative shotgun, manufacturing title "S-12p"
- Adds three 8-round shotgun magazine types: Buckshot, Stun Slug, and 'Dragon's Breath' (Incendiary)
- sAK and S-12 have identical TC prices, offering a decent variety in loadout selection and notably a replacement for the 'necessity e-guns' on the syndie shuttle.
- Semi-automatic shotgun available in the protolathe with enough syndicate reverse-engineering (level 5)
[Buckshot and stun magazines included]

![1](https://cloud.githubusercontent.com/assets/7247232/2806847/46c38476-ccd5-11e3-8108-8510f9a95178.png) ![2](https://cloud.githubusercontent.com/assets/7247232/2806848/46c4514e-ccd5-11e3-8684-8b9067c1907d.png)
![3](https://cloud.githubusercontent.com/assets/7247232/2806849/46c5c0ba-ccd5-11e3-879a-3d4970048a47.png) ![4](https://cloud.githubusercontent.com/assets/7247232/2806850/46c646d4-ccd5-11e3-87fb-c2760988bfeb.png)

Robrichards: Silencer code redux
Nienhaus: Main spriting
Pandarsenic: Magazine sprites
MrSnapwalk: Inhand sprites