Darkness Fixes & Shell Tweaks (#2066)

changes:

ChangeTurf no longer breaks lighting when switching from statically lit turfs to dynamically lit turfs.
Human-types' is_noisy value is now updated on spawn; boots should now make footstep SFX without having to take them off and put them back on.
Fixed a logic error in is_noisy calculations which could have lead to false-negatives.
Shells can now wear socks & undershirts.
Fixed a bug where changing the dynamic lighting status on an area would attempt to build lighting overlays for the entire map.
Fixes #2027.
Fixes #1982.

code/modules/lighting/lighting_area.dm

@@ -17,12 +17,12 @@
 	dynamic_lighting = new_dynamic_lighting
 
 	if (new_dynamic_lighting)
-		for (var/turf/T in turfs)
+		for (var/turf/T in src)
 			if (T.dynamic_lighting)
 				T.lighting_build_overlay()
 
 	else
-		for (var/turf/T in turfs)
+		for (var/turf/T in src)
 			if (T.lighting_overlay)
 				T.lighting_clear_overlay()
 

code/modules/mob/living/carbon/human/human_movement.dm

@@ -127,7 +127,7 @@
 	. = ..()
 	if (is_noisy)
 		var/turf/T = get_turf(src)
-		if (T.x == last_x && T.y == last_y)
+		if ((T.x == last_x && T.y == last_y) || !T.footstep_sound)
 			return
 		last_x = T.x
 		last_y = T.y

code/modules/mob/living/carbon/human/inventory.dm

@@ -437,8 +437,4 @@ This saves us from having to call add_fingerprint() any time something is put in
 	if (shoes:silent)
 		return
 
-	var/turf/T = get_turf(src)
-	if (!istype(T) || !T.footstep_sound)
-		return
-
 	is_noisy = TRUE

code/modules/mob/living/carbon/human/species/station/machine_subspecies.dm

@@ -35,7 +35,7 @@
 		"Your synthetic flesh crawls in the heat, swelling into a disgusting morass of plastic."
 		)
 
-	appearance_flags = HAS_HAIR_COLOR | HAS_SKIN_TONE | HAS_EYE_COLOR | HAS_FBP
+	appearance_flags = HAS_HAIR_COLOR | HAS_SKIN_TONE | HAS_EYE_COLOR | HAS_FBP | HAS_UNDERWEAR | HAS_SOCKS
 
 	has_limbs = list(
 		"chest" =  list("path" = /obj/item/organ/external/chest/shell),