2.35.4 (unstable):

* Document:
  - Add process_xinclude(), using new XIncludeStart
    and XIncludeEnd classes, derived from Node.
    (Kjell Ahlsted) Bug #338521.
  - Make the Document(xmlDoc*) constructor public.
    (Kjell Ahlsted) Bug #668980.
* Parser: Make it thread-safe.
  (Kjell Ahlstedt) Bug #681467.
* Schema::set_document(): If the argument 'document' is 0 then
  create an empty document, as the documentation says.
  (Kjell Ahlstedt)
* Improve the error handling.
  (Kjell Ahlstedt) Bug #635846.
* Documentation:
  - Add incremental parsing to the SaxParser example program.
  - DtdValidation and SchemaValidation: Print all exception information.
  - Improve error descriptions.
    (Kjell Ahlstedt)