muse-latex: Add footnotes to links so that they show up on printed copies.
* lisp/muse-latex.el (muse-latex-markup-strings): Add string for
'url-and-desc. Display footnotes if we have both a link and a
description, since we want URLs to show up on printed documents.
(muse-latex-markup-specials-document): Escape the "@" character in the
entire document.
* lisp/muse-publish.el (muse-publish-url): Distinguish between URLs
without descriptions and URLs with descriptions. If no markup string
exists for 'url-and-desc, fall back to 'url.
git-archimport-id: mwolson@gnu.org--2006/muse--main--1.0--patch-63