Jumbo patch, extended regression tests and fixed regression results:

- configure.in tests/Makefile.am tests/XSLTMark/* tests/multiple:
  added the XSLTMark in the regression tests as well as multiple
  output test from Ankh
- libxslt/functions.c libxslt/keys.c libxslt/transform.c
  libxslt/variables.c libxslt/xsltutils.c: applied William M. Brack
  patches and fixed a memory leak
- tests/docbook/result/html/*.html : updated the results after
  William's patch
- tests/xmlspec/REC-xml-20001006-review.html
  tests/xmlspec/REC-xml-20001006.html: libxml now don't invent
  an HTML doctype when serializing HTML result, but adds the
  encoding in ALT
Daniel