Fix display, inform player of offline turrets, list non-hardcoded fuels

Fixed that display shifting bug when configuring turrets in a moving vehicle.

When vehicle turret system is turned on, but all its turrets are off, a warning is printed.

Fuel tanks containing substances that weren't hardcoded are now displayed below the hardcoded ones (so you can see an acid gauge, for example). Their colors are taken from the default ammo of their type. Non-ammo types not supported yet.
Converse needed: on closing the turret panel, or perhaps in it: "Turret(s) configured to shoot, but turret system is off." or somesuch.  Basically, make sure people know that activating the turrets individually won't get them firing by itself.