Gallery_View base class from Theme_View and Admin_View.
1) Move all the theme specific jquery stuff from gallery_theme::head()
and admin_head() into the theme files. Use $theme->script() as
appropriate.
2) Get rid of the extra boolean on $theme->url() that we were using so
that we could call $theme->script($theme->url(...)) -- add
$theme->theme_script() instead (poorly named, but still clearer than
what we had before)
3) Fix the bug that combined scripts didn't work at all in the admin
theme.
4) Get rid of $theme->display() in favor of new View(...)
