Adds some new tile types, grates. Fixes #3332 (#8263)

This pr adds some assets that are not mapped in yet, but are to be used in future projects among other things.

Added a new type of linoleum, rubber carpets, dark/light metal grates. Added some proper footramp damaged states.
Makes blue/green (circuit/strata) tiles craftable somehow like requested here, though via autolathe instead.
Blown up footramps will no longer result in a 'Fix me!' icon appearing.

code/game/objects/structures/lattice.dm

@@ -64,8 +64,8 @@
 	desc = "A catwalk for easier EVA maneuvering."
 	icon = 'icons/obj/smooth/catwalk.dmi'
 	icon_state = "catwalk"
-	smooth = SMOOTH_MORE
-	canSmoothWith = list(/obj/structure/lattice/catwalk)
+	smooth = TRUE
+	canSmoothWith = null
 
 // Special catwalk that can be placed on regular flooring.
 /obj/structure/lattice/catwalk/indoor
@@ -98,3 +98,60 @@
 		var/atom/movable/AM = A
 		AM.forceMove(dest)
 	..()
+
+/obj/structure/lattice/catwalk/indoor/grate
+	name = "grate"
+	desc = "A metal grate."
+	icon = 'icons/obj/grate.dmi'
+	icon_state = "grate_dark"
+	smooth = null
+	var/base_icon_state = "grate_dark"
+	var/damaged = FALSE
+
+/obj/structure/lattice/catwalk/indoor/grate/old
+	icon_state = "grate_dark_old"
+
+/obj/structure/lattice/catwalk/indoor/grate/damaged
+	icon_state = "grate_dark_dam0"
+	damaged = TRUE
+
+/obj/structure/lattice/catwalk/indoor/grate/damaged/Initialize()
+	.=..()
+	icon_state = "[base_icon_state]_dam[rand(0,3)]"
+
+/obj/structure/lattice/catwalk/indoor/grate/light
+	icon_state = "grate_light"
+	base_icon_state = "grate_light"
+
+/obj/structure/lattice/catwalk/indoor/grate/light/old
+	icon_state = "grate_light_old"
+
+/obj/structure/lattice/catwalk/indoor/grate/light/damaged
+	icon_state = "grate_light_dam0"
+	damaged = TRUE
+
+/obj/structure/lattice/catwalk/indoor/grate/light/damaged/Initialize()
+	.=..()
+	icon_state = "[base_icon_state]_dam[rand(0,3)]"
+
+/obj/structure/lattice/catwalk/indoor/grate/attackby(obj/item/C, mob/user)
+	if(C.iswelder() && damaged)
+		var/obj/item/weldingtool/WT = C
+		if(do_after(user, 5/C.toolspeed, act_target = src) && WT.remove_fuel(1, user))
+			to_chat(user, span("notice","You slice apart the [src] leaving nothing useful behind."))
+			playsound(src, 'sound/items/Welder.ogg', 50, 1)
+			qdel(src)
+	else
+		..()
+
+/obj/structure/lattice/catwalk/indoor/grate/ex_act(severity)
+	switch(severity)
+		if(1.0)
+			qdel(src)
+		if(2.0)
+			if(!damaged)
+				icon_state = "[base_icon_state]_dam[rand(0,3)]"
+				damaged = TRUE
+			else
+				qdel(src)
+	return