TG: Added Invisty's Emitter sprites.

Cleaned up part of the door code and moved some defines to their proper files.
Firelocks can now be welded open and now shows the welded overlay properly.
Borgs can now properly mess with door wiring. r2895

code/modules/power/singularity/emitter.dm

@@ -2,7 +2,7 @@
 	name = "Emitter"
 	desc = "A heavy duty industrial laser"
 	icon = 'singularity.dmi'
-	icon_state = "Emitter"
+	icon_state = "emitter"
 	anchored = 0
 	density = 1
 	req_access = list(access_engine)
@@ -39,9 +39,9 @@
 
 	update_icon()
 		if (active && !(stat & (NOPOWER|BROKEN)))
-			icon_state = "Emitter +a"
+			icon_state = "emitter_+a"
 		else
-			icon_state = "Emitter"
+			icon_state = "emitter"
 
 
 	attack_hand(mob/user as mob)