[ansel] gallery ordering issue

[Ben Chavet]

> You could put "dummy" entries into the datatree for each gallery as 
> images and
> use those as the parents for the image objects, so sort of maintaining
> a mirror
> tree of the gallery structure.

I think what would help the most, would be a modification to the datatree
driver.  Currently, when you get a list of top-level objects, it grabs the
immediate children of those objects, too.  If we could force it to only grab
the top-level objects, the parent->child relationship would be possible 
without
a performance hit.

Of course, if we did go the "dummy" tree route, we could drop the 'gallery'
attribute of an image & be able to have an image in multiple galleries without
having to store multiple copies.  I'll work on implementing this & see what
kind of performance I can get out of it.

--Ben