Fix #712: ability to return to previous image if home/end was pressed occasionally

Fix #712: ability to return to previous image if home/end was pressed occasionally

https://github.com/BestImageViewer/geeqie/issues/712

Additional Go menu items - Image Back, Image Forward

Remove key bindings for multi-page navigation - they conflict with other
usage. The user can set their own key bindings.

Remove enable/disable multi-page navigation items. The parameter
fd->page_total is set in another thread which causes problems. It is
easiest to leave them always enabled.