Correct po file to work with docbook.

 - Remove <a href=...>, which should be <ulink> instead and only if
   they are present in the original.  The links should be the same in
   the English and French version.

 - Rewrite <i> to <citetitle>.  Might be better to remove them.

 - Rewrite <sup><small> to <superscript>.

 - Add some missing indexterm markers in an endnote.