Committing for Numbers.

- Readded Volume Pumps - now they work as intended and are constructable
- Readded Passive Gates - now they work as intended and are constructable
- Readded Heat Exchangers - now they work as intended and are constructable
- Added Heater - to warm up gasses to 300C
- Adjusted volumes on big tanks and portable pumps to 2000 and 1200 respectably
- Pipe dispensers can produce the readded pieces.
- Pipe construction code updated to compesate for the new items
- New graphics for all of the above - courtesy by Ausops.

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@4785 316c924e-a436-60f5-8080-3fe189b3f50e

code/ATMOSPHERICS/components/unary/heat_exchanger.dm

@@ -63,4 +63,27 @@
 			if(abs(other_old_temperature-partner.air_contents.temperature) > 1)
 				partner.network.update = 1
 
-		return 1
+		return 1
+
+	attackby(var/obj/item/weapon/W as obj, var/mob/user as mob)
+		if (!istype(W, /obj/item/weapon/wrench))
+			return ..()
+		var/turf/T = src.loc
+		if (level==1 && isturf(T) && T.intact)
+			user << "\red You must remove the plating first."
+			return 1
+		var/datum/gas_mixture/int_air = return_air()
+		var/datum/gas_mixture/env_air = loc.return_air()
+		if ((int_air.return_pressure()-env_air.return_pressure()) > 2*ONE_ATMOSPHERE)
+			user << "\red You cannot unwrench this [src], it too exerted due to internal pressure."
+			add_fingerprint(user)
+			return 1
+		playsound(src.loc, 'sound/items/Ratchet.ogg', 50, 1)
+		user << "\blue You begin to unfasten \the [src]..."
+		if (do_after(user, 40))
+			user.visible_message( \
+				"[user] unfastens \the [src].", \
+				"\blue You have unfastened \the [src].", \
+				"You hear ratchet.")
+			new /obj/item/pipe(loc, make_from=src)
+			del(src)