* [DBNL,EXT] Started adding the DTD.
* [DBNL,EXT] The content of chapter pages is now rewritten to a DBNL-specific XML format, defined by a DTD, using XLink for images.
* [DBNL,EXT] Started inserting the footnotes into the running text.
* [XLINK,NEW] New module supporting the XLink 1.1 vocabulary.
* [XML,NEW] Added dom_to_xml_file/[3,4].