besides performance in some cases.
* DAG_scene_sort is now removed and replaced by DAG_relations_tag_update in
most cases. This will clear the dependency graph, and only rebuild it right
before it's needed again when the scene is re-evaluated.
This is done because DAG_scene_sort is slow when called many times from
python operators. Further the scene argument is not needed because most
operations can potentially affect more than the current scene.
* DAG_scene_relations_update will now rebuild the dependency graph if it's not
there yet, and DAG_scene_relations_rebuild will force a rebuild for the rare
cases that need it.
* Remove various places where ob->recalc was set manually. This should go
through DAG_id_tag_update() in nearly all cases instead since this is now
a fast operation. Also removed DAG_ids_flush_update that goes along with
such manual tagging of ob->recalc.
As far as I could tell, these were really only still used for "virtual
modifiers", though we really don't use these anymore. Instead, most of the time,
people need to set these settings in armature modifiers directly (these didn't
even get copied over in that case). This was a source of confusion and
redundancy, so removing these now.
This change can be reverted if these were actually of some use out there...
- object updates were not being flushed, so children weren't updating.
- apply the matrix relative to the parent, added this as an option to object_apply_mat4() which allows assigning the worldspace matrix in python without worrying about the parent.
