OSJC's US grenade skin. + Ammo heath and armor

BAsically a higher-res US grenade!

also while I was at it I nocked up a texture for the potato-masher nade ammo model, based off of an altered tehsnake skin (also included) and then the nade bag started to look in need of a touch up so I did those, then the healthbags looked odd and with the mp40 mag-pouches getting lonely I did those too. Finally as requested I re-textured the armour too! rather than seperate the skins I've compiled them with the nade...