makes the game compile

fixes more icon paths
I gave zvent the vent_map icon as a placeholder because it's not like it's even used anyway

code/game/objects/structures/transit_tubes/transit_tube_construction.dm

@@ -92,7 +92,7 @@
 // transit tube station
 /obj/structure/c_transit_tube/station
 	name = "unattached through station"
-	icon = 'icons/obj/pipes/transit_tube_station.dmi'
+	icon = 'icons/obj/atmospherics/pipes/transit_tube_station.dmi'
 	icon_state = "closed"
 
 /obj/structure/c_transit_tube/station/tube_turn(var/angle)
@@ -122,7 +122,7 @@
 // in that sense they're the same as stations and can reuse their flip and rotate verbs
 /obj/structure/c_transit_tube/station/block
 	name = "unattached tube blocker"
-	icon = 'icons/obj/pipes/transit_tube.dmi'
+	icon = 'icons/obj/atmospherics/pipes/transit_tube.dmi'
 	icon_state = "Block"
 
 /obj/structure/c_transit_tube/station/block/buildtube()
@@ -136,7 +136,7 @@
 //see station.dm for the logic
 /obj/structure/c_transit_tube_pod
 	name = "unattached transit tube pod"
-	icon = 'icons/obj/pipes/transit_tube_pod.dmi'
+	icon = 'icons/obj/atmospherics/pipes/transit_tube_pod.dmi'
 	icon_state = "pod"
 	anchored = 0.0
 	density = 0