Fix headlights not turning off for vehicules without electricity.

The function that toggled the lights on and off checked if the lights
were off or if the vehicule has some batteries left before toggling the
lights. This allowed vehicules without batteries to turn on their lights
but are not able to turn it off.

Fixed by checking if the lights were off instead.
Adds caseless light machine gun and spawns.
Sleep now intensifies recovery based on time spent sleeping.
Changed formula so sleep recovery increases over 2 hours to 2x, and removed
fatigue while sleeping and attempting to sleep. 7.25 hours continuous rest
required for a full 16 hour day, giving some leeway for activities that
might increase fatigue, and extended recovery is slightly faster.
Fixed natural healing.
Merge adaptive resting based on fatigue level.

Conflicts:
	src/game.cpp