* FEATURES: updated
* libxslt/xsltutils.c: do not dump document for which there have
  been no generated content
* tests/multiple/result.xml tests/namespaces/extra2.out: fixed
  test output accordingly
* libxslt/transform.c libxslt/preproc.c: added xsl:fallback support
* tests/REC/Makefile.am tests/REC/test-15-1.*: xsl:fallback test
* tests/xmlspec/Makefile.am tests/docbook/Makefile.am: cleanups
Daniel