Attached patch affects how 'info' links in org mode are converted to HTML
links.  Today info links such as

    [[info:emacs#List Buffers]]

are converted to this HTML link:

    <a href="emacs.html#List-Buffers">emacs#List Buffers</a>

With the patch applied, the HTML link generated would be

    <a href="
http://www.gnu.org/software/emacs/manual/html_mono/emacs.html#List-Buffers">emacs#List
Buffers</a>

The general idea is that couple of list variables describe how to map
info file names to URLs so that those URL's would be used if available.

One motivation for this patch is to make it easy for elisp package
authors to to create links to wonderful emacs documents, because writing
an org info-link to emacs manual in org files is trivial once you know
the info node name.