For the file_list action, include the pages which link to the given file(s).
This required rejiggering so that that information is actually retained in the database.
Unfortunately, you'll actually need to revise the page(s) in question, because that's the
only time this information is updated in the database.
Deleting a page removes all revisions of that page.
Deleting a Web removes all pages (and all revisions thereof)
and all wiki_files belonging to that Web.
The file upload dialog asks for a description of the image or file to be uploaded. Use this as the default alt-text for the image and as a title attribute for a file link.
