Allow code-blocks in footnotes for LaTeX PDF output.
This is done via using a ``footnote environment``, provided by LaTeX
package footnotehyper which replaces old problematic package footnote.
No need to ship a custom tabulary anymore.
The footnote markers are silently removed from the table of contents and
do not end in the PDF bookmarks (the old code in ``sphinx.sty`` copying
``footmisc.sty`` was not satisfactory and has been deleted and replaced
by use of better ``\sphinxfootnotemark``.) Footnotes can be used also in
captions of literal blocks.
Jean-François B
b8e0e935e4