Update changelog
Tweaked hunger and fatigue's contribution to body temperature
Updated update_bodytemp() opening comment to reflect recent changes
Update changelog
Updated itypedef.cpp -- added hats

Added the beret and the pickelhaube. One is for military and fashion spawns, the other for the pawnshop (and maybe one day museums?).
Lone gas stations can now rotate
Update mapitemsdef.cpp -- Added hats

Added the pickelhaube and the beret to the relevant spawn lists (to mi_pawn and mi_mil_armor).
New overlap::is_road_or_highway function to reduce duplicate code

Used in omspec_place::by_highway and overmap::place_special
Remove unused variable warnings
Add multiplier to moster group entries.
Extract new multiplier property from monster group entries.
Scale monster spawns based on monster group entry multiplier property.
Merge batch of bugfixes.
Merge metabolism boost.
Merge tweak of hunger and fatigue termperature effect.

Conflicts:
	data/changelog.txt
Merge mutation-based temperature effects.

Conflicts:
	data/changelog.txt
MErge in some hats.
Fix another batch of shadowed variables
Changed artifact saving to use json, to allow easy storage of the arbitrary
strings that can appear in names/descriptions.

Closes #357
Remove old artifact loading code