Fixed recentf-edit-list and recentf-open-more-files

Fixed recentf-edit-list and recentf-open-more-files
commands.  Require `wid-edit' at run-time.

Added some "Commentary".
(recentf-open-more-files, recentf-edit-list): Minor changes to
move the point at the top of the file list.  This behaviour is
consistent with the menu one when the list contains a lot of
files.
(recentf-cleanup): Now displays the number of items removed from
the list.
(recentf-relative-filter) New menu filter to show filenames
relative to `default-directory'.