Re-worked featured items display to load like everything else

- reordered/added the loading progress stuff to showfeatured()
- adjusted jquery slidepanel animation speed (faster) (unrelated
  commit bundled in this one. oops.)
- fixed margin on images in featured item grid display
- removed "shuffle items" button. No need (and it added clutter)

Signed-off-by: William Rockwood <wrockwood@tadl.org>