Atmos machine update

Takes a pass at updating ATMOSPHERICS to take advantage of the new powernet changes.

Also removes var/on definitions from many atmos machines. Machines generally shouldn't
be doing "on" things if they aren't using power, and most players don't expect a machine
to use power if it isn't "on," so I guess this is fair game.

Also, further refactoring.

code/modules/admin/verbs/debug.dm

@@ -1007,7 +1007,7 @@ But you can call procs that are of type /mob/living/carbon/human/proc/ for that
 					Pump.air2.gas["nitrogen"] = 3750	//The contents of 2 canisters.
 					Pump.air2.temperature = 50
 					Pump.air2.update_values()
-				Pump.on=1
+				Pump.use_power=1
 				Pump.target_pressure = 4500
 				Pump.update_icon()