Allows the sliding of pipework along floors

Allows pipes to be slid along the floor, not only does this make laying
pipes easier, but you can now lay pipes under machinery without having
to remove them.

code/game/turfs/simulated/floor.dm

@@ -582,4 +582,20 @@ turf/simulated/floor/proc/update_icon()
 					burnt = 0
 					broken = 0
 				else
-					user << "\blue You need more welding fuel to complete this task."
+					user << "\blue You need more welding fuel to complete this task."
+
+	if(istype(C,/obj/item/pipe))
+		var/obj/item/pipe/V = C
+		if(V.pipe_type != -1) // ANY PIPE
+			var/obj/item/pipe/P = C
+
+			user.visible_message( \
+				"[user] starts sliding a [P] along \the [src].", \
+				"\blue You slide a [P] along \the [src].", \
+				"You hear the scrape of metal against something.")
+			user.drop_item()
+			P.dir = user.dir
+			P.x = src.x
+			P.y = src.y
+			P.z = src.z
+			P.loc = src