switch to use xmlReadfile instead of xmlParseFile, this avoid relying on

* libxslt/documents.c libxslt/imports.c libxslt/xslt.c libxslt/xslt.h
  xsltproc/xsltproc.c: switch to use xmlReadfile instead of
  xmlParseFile, this avoid relying on global parser options, far
  far cleaner.
* tests/XSLTMark/xslbench1.out tests/general/bug-90.out: fixes a
  slightly corrected output for CDATA and STYLE element save.
Daniel