Implement SSatoms

* Moves proc/initialize() from being on /atom/movable, /are and /turf/simulated to being on /atom - Now turfs can initialize too
* Added the SSatoms subsystem which controls initialization of atoms at roundstart and during normal conditions.
* Disabled the old auto_init = 0 behavior, ALL atoms should get initialized() called on them now.
* Refactored the way initialize() is called during /New() to utilize SSatoms instead of SScreation
* Removed SScreation, as it was only a stop-gap until SSatoms could be ported.
* Updated the maploader to inform SSatoms when it is loading maps instead of SScreation.
* Updated the template map loader to use SSatoms to perform initTemplateBounds
* Renamed 'initialized' var in seed_storage to deconflict.
* Removed usage of auto_init = 0, replaced with a no-op initialize() proc for atoms that don't need initialization.

code/modules/maps/tg/reader.dm

@@ -304,7 +304,7 @@ var/global/use_preloader = FALSE
 		first_turf_index++
 
 	//turn off base new Initialization until the whole thing is loaded
-	SScreation.StartLoadingMap()
+	SSatoms.map_loader_begin()
 	//instanciate the first /turf
 	var/turf/T
 	if(members[first_turf_index] != /turf/template_noop)
@@ -323,7 +323,7 @@ var/global/use_preloader = FALSE
 	for(index in 1 to first_turf_index-1)
 		instance_atom(members[index],members_attributes[index],crds,no_changeturf)
 	//Restore initialization to the previous value
-	SScreation.StopLoadingMap()
+	SSatoms.map_loader_stop()
 
 ////////////////
 //Helpers procs
@@ -344,9 +344,9 @@ var/global/use_preloader = FALSE
 
 	//custom CHECK_TICK here because we don't want things created while we're sleeping to not initialize
 	if(TICK_CHECK)
-		SScreation.StopLoadingMap()
+		SSatoms.map_loader_stop()
 		stoplag()
-		SScreation.StartLoadingMap()
+		SSatoms.map_loader_begin()
 
 /dmm_suite/proc/create_atom(path, crds)
 	set waitfor = FALSE