2.6.22: Sep 12 2005:
   - build fixes: compile without schematron (Stéphane Bidoul)
   - bug fixes: xmlDebugDumpNode on namespace node (Oleg Paraschenko)i,
      CDATA push parser bug, xmlElemDump problem with XHTML1 doc, 
      XML_FEATURE_xxx clash with expat headers renamed XML_WITH_xxx,
      fix some output formatting for meta element (Rob Richards),
      script and style XHTML1 serialization (David Madore), Attribute
      derivation fixups in XSD (Kasimier Buchcik), better IDC error
      reports (Kasimier Buchcik)
      
   - improvements: add XML_SAVE_NO_EMPTY xmlSaveOption (Rob Richards),
      add XML_SAVE_NO_XHTML xmlSaveOption, XML Schemas improvements
      preparing for derive (Kasimier Buchcik).
   - documentation: generation of gtk-doc like docs, integration with
      devhelp.