Make arrow/bolt range mainly determined by the weapon, not the ammo
Coilguns have 3x range as well as 3x damage

If we're making coilguns require battery charges, we should really have them buffed compared to nailguns. A range buff seemed appropriate, and 3x the nailgun's range matches up nicely with the existing damage buff.
Merge pull request #871 from atomicdryad/gun-range2_son_of_gun-range

re-push ddb088c and a14eb58 (gun-range), which author clobbered in 4e8f6b3 (add missing prices)