Custom ammo textures

[dninemfive]

Make custom textures for all the new ammo types. The following are currently planned and/or implemented:

• [ ] FGR-17 Viper
• [ ] M60E3
• [ ] M203/40mm HEDP
• [ ] M224 60mm
• [ ] XM-35 105mm
• [ ] M119 105mm
• [ ] ARES 75mm
• [ ] Barret M82/.50 RAUFOSS