zombie siege (Guns in minecraft loot chests)

changed the chance of not getting a gun to around 25% - 33% and changed the amount of ammo received from a chest to match a more realistic amount. pistol: 13 - 64 shotguns: 10 - 36 assault rifles: 16 - 64 smgs: 32 - 64 snipers: 6 - 20 machine guns: 64 - 256