Turns events into vars instead of a list, to greatly simplify qdel() cleanup.

code/controllers/Processes/scheduler.dm

@@ -28,16 +28,13 @@
 	stat(null, "[scheduled_tasks.len] task\s")
 
 /datum/controller/process/scheduler/proc/schedule(var/datum/scheduled_task/st)
-	if(world.time < st.trigger_time)
-		scheduled_tasks += st
-		st.register(OBSERVER_EVENT_DESTROY, src, /datum/controller/process/scheduler/proc/unschedule)
-	else
-		st.process()
+	scheduled_tasks += st
+	st.destruction.register(src, /datum/controller/process/scheduler/proc/unschedule)
 
 /datum/controller/process/scheduler/proc/unschedule(var/datum/scheduled_task/st)
 	if(st in scheduled_tasks)
 		scheduled_tasks -= st
-		st.unregister(OBSERVER_EVENT_DESTROY, src)
+		st.destruction.unregister(src)
 
 /**********
 * Helpers *
@@ -98,7 +95,7 @@
 
 /datum/scheduled_task/source/New(var/trigger_time, var/datum/source, var/procedure, var/list/arguments, var/proc/task_after_process, var/list/task_after_process_args)
 	src.source = source
-	src.source.register(OBSERVER_EVENT_DESTROY, src, /datum/scheduled_task/source/proc/source_destroyed)
+	src.source.destruction.register(src, /datum/scheduled_task/source/proc/source_destroyed)
 	..(trigger_time, procedure, arguments, task_after_process, task_after_process_args)
 
 /datum/scheduled_task/source/Destroy()

code/controllers/observer_listener/datum/observer.dm

@@ -1,41 +0,0 @@
-#define OBSERVER_EVENT_DESTROY "OnDestroy"
-
-/datum
-	var/list/observer_events
-
-/datum/Destroy()
-	raise_event(OBSERVER_EVENT_DESTROY, list(src))
-	for(var/list/listeners in observer_events)
-		listeners.Cut()
-
-	return ..()
-
-/datum/proc/register(var/event, var/procOwner, var/proc_call)
-	var/list/listeners = get_listener_list_from_event(event, TRUE)
-	listeners[procOwner] = proc_call
-
-/datum/proc/unregister(var/event, var/procOwner)
-	var/list/listeners = get_listener_list_from_event(event, FALSE)
-	listeners -= procOwner
-
-/datum/proc/raise_event(var/event, var/list/args = list())
-	var/list/listeners = get_listener_list_from_event(event, FALSE)
-	if(listeners)
-		for(var/listener in listeners)
-			call(listener, listeners[listener])(arglist(args))
-
-/datum/proc/get_listener_list_from_event(var/observer_event, var/create_list)
-	if(!observer_events)
-		if(create_list)
-			observer_events = list()
-		else
-			return
-
-	var/list/listeners = observer_events[observer_event]
-	if(!listeners)
-		if(create_list)
-			listeners = list()
-			observer_events[observer_event] = listeners
-		else
-			return
-	return listeners