machinery_process() & auto_use_power efficiency tweaks (#2657)

changes:

Machinery now uses machinery_process() instead of process(), allowing machines to be put into SSprocessing-style lists in addition to the machinery list.
Automatic power calculations now involve less proc-calls.

code/modules/shieldgen/emergency_shield.dm

@@ -17,7 +17,7 @@
 	desc = "A weak forcefield which seems to be projected by the station's emergency atmosphere containment field"
 	health = max_health/2 // Half health, it's not suposed to resist much.
 
-/obj/machinery/shield/malfai/process()
+/obj/machinery/shield/malfai/machinery_process()
 	health -= 0.5 // Slowly lose integrity over time
 	check_failure()
 
@@ -180,7 +180,7 @@
 		create_shields()
 	update_icon()
 
-/obj/machinery/shieldgen/process()
+/obj/machinery/shieldgen/machinery_process()
 	if (!active || (stat & NOPOWER))
 		return
 

code/modules/shieldgen/sheldwallgen.dm

@@ -79,7 +79,7 @@
 	power = 1	// IVE GOT THE POWER!
 	return 1
 
-/obj/machinery/shieldwallgen/process()
+/obj/machinery/shieldwallgen/machinery_process()
 	power()
 	if(power)
 		storedpower -= 2500 //the generator post itself uses some power

code/modules/shieldgen/shield_capacitor.dm

@@ -97,7 +97,7 @@
 	user << browse(t, "window=shield_capacitor;size=500x400")
 	user.set_machine(src)
 
-/obj/machinery/shield_capacitor/process()
+/obj/machinery/shield_capacitor/machinery_process()
 	if (!anchored)
 		active = 0
 

code/modules/shieldgen/shield_gen.dm

@@ -134,7 +134,7 @@
 	user << browse(t, "window=shield_generator;size=500x400")
 	user.set_machine(src)
 
-/obj/machinery/shield_gen/process()
+/obj/machinery/shield_gen/machinery_process()
 	if (!anchored && active)
 		toggle()