Corrects some plane and layer issues

code/game/objects/structures/catwalk.dm

@@ -1,10 +1,11 @@
 // Based on catwalk.dm from https://github.com/Endless-Horizon/CEV-Eris
 /obj/structure/catwalk
-	layer = TURF_LAYER + 0.5
-	icon = 'icons/turf/catwalks.dmi'
-	icon_state = "catwalk"
 	name = "catwalk"
 	desc = "Cats really don't like these things."
+	plane = TURF_PLANE
+	layer = ABOVE_UTILITY
+	icon = 'icons/turf/catwalks.dmi'
+	icon_state = "catwalk"
 	density = 0
 	var/health = 100
 	var/maxhealth = 100

code/game/objects/structures/grille.dm

@@ -7,7 +7,7 @@
 	anchored = 1
 	flags = CONDUCT
 	pressure_resistance = 5*ONE_ATMOSPHERE
-	layer = UNDER_JUNK_LAYER
+	layer = TABLE_LAYER
 	explosion_resistance = 1
 	var/health = 10
 	var/destroyed = 0

code/game/objects/structures/signs.dm

@@ -3,8 +3,7 @@
 	anchored = 1
 	opacity = 0
 	density = 0
-	plane = TURF_PLANE
-	layer = ABOVE_TURF_LAYER
+	layer = UNDER_JUNK_LAYER
 	w_class = ITEMSIZE_NORMAL
 
 /obj/structure/sign/ex_act(severity)