PDF generation fails if a header text is repeated due to TOC numbering in headings

If a header (example: "1.1 Description") is repeated, the pdf generation fails due to the repeated id and name in the generated anchor that's defined in radeox_markup_xwiki.properties at filter.heading.print.

This occurred frequently when all inclusive documents where defined by including other documents in the wiki. Several of the included documents had identicall headings.