Give story and tag objects is_tag value
Keep selection in interface, no matter what

This used to be accomplished by forcing the daemon to keep items
indefinitely but that was removed (themoken/canto-next@2b78e98).

- Tag sync now keeps selection items in order, regardless of whether the
  selection is in TagCore.

- Because the Tag ordering works so much better when sync() is done with
  full items available, it's no longer possible for a user to request a
reset when an update is still in progress.

- Attributes (controlled by tag_updater) are now kept until the items
  are disposed of by the Tag objects, not the TagCore objects.

- Old selection keeping overhead removed.