Top-bar dropdown images now link to pages

Top-bar dropdown images now link to pages

To avoid uprooting the menu walker which uses before (and not
actual img elements which could be clicked), and to avoid having
to wrap the li or its contents in an anchor somehow, I added some
jquery to make the entire menu-item li direct to the href of its
child anchor, to emulate this being done through clicking on the
image. Also added a cursor pointer.