Add debug light source/corner/overlay instance count

code/modules/lighting/lighting_source.dm

@@ -1,3 +1,4 @@
+/var/list/datum/light_source/all_lighting_sources = list()
 // This is where the fun begins.
 // These are the main datums that emit light.
 
@@ -31,6 +32,7 @@
 	var/force_update
 
 /datum/light_source/New(var/atom/owner, var/atom/top)
+	all_lighting_sources += src
 	source_atom = owner // Set our new owner.
 	if(!source_atom.light_sources)
 		source_atom.light_sources = list()
@@ -55,10 +57,12 @@
 
 	update()
 
+
 	return ..()
 
 // Kill ourselves.
 /datum/light_source/proc/destroy()
+	all_lighting_sources -= src
 	destroyed = TRUE
 	force_update()
 	if(source_atom)