-Call spumux.
+Add keyboard command for "top menu" in preview mode.
+Add support for videos in preview mode.
Disable scrollbars (not sure how how to do this).
-Call dvdauthor.
May need to override default menu navigation actions because dvdauthor
seems to cause rather undesirable behaviour when buttons are not
arranged in a grid.
+Search whole of history rather than just previous page when deciding whether a link goes back or forward.
+For any page with no links, add a "back" link (this raises the issue of localisation, of course).
+If a page is too large, split it and add "next" and "previous" links (seems very difficult).