Modify fire_act to temperature_expose where needed

This commit changes a bunch of objects fire_act's to temperature_expose,
to allow for superhot gas to act like an actual hotspot. This behaviour is
consistant with -tg-.

code/game/objects/structures/false_walls.dm

@@ -261,6 +261,16 @@
 	mineral = "plasma"
 	walltype = "plasma"
 
+/obj/structure/falsewall/plasma/proc/burnbabyburn(user)
+	playsound(src, 'sound/items/Welder.ogg', 100, 1)
+	atmos_spawn_air(SPAWN_HEAT | SPAWN_TOXINS, 400)
+	new /obj/structure/girder/displaced(loc)
+	qdel(src)
+
+/obj/structure/falsewall/plasma/temperature_expose(datum/gas_mixture/air, exposed_temperature, exposed_volume)
+	if(exposed_temperature > 300)
+		burnbabyburn()
+
 //-----------wtf?-----------start
 /obj/structure/falsewall/clown
 	name = "bananium wall"

code/game/objects/structures/grille.dm

@@ -258,7 +258,7 @@
 			return 0
 	return 0
 
-/obj/structure/grille/fire_act(datum/gas_mixture/air, exposed_temperature, exposed_volume)
+/obj/structure/grille/temperature_expose(datum/gas_mixture/air, exposed_temperature, exposed_volume)
 	if(!destroyed)
 		if(exposed_temperature > T0C + 1500)
 			health -= 1

code/game/objects/structures/window.dm

@@ -381,7 +381,7 @@ var/global/wcColored
 /obj/structure/window/update_icon()
 	return
 
-/obj/structure/window/fire_act(datum/gas_mixture/air, exposed_temperature, exposed_volume)
+/obj/structure/window/temperature_expose(datum/gas_mixture/air, exposed_temperature, exposed_volume)
 	if(exposed_temperature > T0C + 800)
 		hit(round(exposed_volume / 100), 0)
 	..()