Body temperature fixes and updates

Body temperature regulation is now based on species, and environmental
temperature now respects the air density when affecting living/humans.
This also fixes some bugs with heat/cold protection handling and
improves the way synthetic species body temperatures are handled to be
much more logical.

IPCs always gain temperature but cool down because of their environment.
When the heat transfer to the environment is reduced because of the lack
of air, this will cause IPCs to heat up.

As well, having an infection will increase your body temperature, and
body scanners now detect infections.

code/game/objects/items/devices/scanners.dm

@@ -161,7 +161,7 @@ REAGENT SCANNER
 			if(e.status & ORGAN_BROKEN)
 				if(((e.name == "l_arm") || (e.name == "r_arm") || (e.name == "l_leg") || (e.name == "r_leg")) && (!(e.status & ORGAN_SPLINTED)))
 					user << "\red Unsecured fracture in subject [limb]. Splinting recommended for transport."
-			if(e.is_infected())
+			if(e.has_infected_wound())
 				user << "\red Infected wound detected in subject [limb]. Disinfection recommended."
 
 		for(var/name in H.organs_by_name)