* xmlwriter.c include/libxml/xmlwriter.h: applied patch from
Alfred Mickautsch, bugfixes and comments
* doc/examples/*: added his test as the xmlWriter example
* doc/html/ doc/*.html: this resulted in some improvements
* include/libxml/hash.h: fixed an inclusion problem when
<libxml/hash.h> wasn't preceeded by <xml/parser.h>
Daniel
