applied patch from Alfred Mickautsch, bugfixes and comments added his test

* 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
diff --git a/doc/APIchunk23.html b/doc/APIchunk23.html
index 01df70a..2d36842 100644
--- a/doc/APIchunk23.html
+++ b/doc/APIchunk23.html
@@ -31,8 +31,8 @@
 <a href="APIchunk21.html">q-r</a>
 <a href="APIchunk22.html">s-s</a>
 <a href="APIchunk23.html">t-t</a>
-<a href="APIchunk24.html">u-v</a>
-<a href="APIchunk25.html">w-x</a>
+<a href="APIchunk24.html">u-w</a>
+<a href="APIchunk25.html">x-x</a>
 </h2><h2>Letter t:</h2><dl><dt>tag</dt><dd><a href="html/libxml-HTMLparser.html#_htmlElemDesc">_htmlElemDesc</a><br />
 <a href="html/libxml-HTMLparser.html#htmlAutoCloseTag">htmlAutoCloseTag</a><br />
 <a href="html/libxml-HTMLparser.html#htmlIsAutoClosed">htmlIsAutoClosed</a><br />
@@ -417,6 +417,6 @@
 <a href="APIchunk21.html">q-r</a>
 <a href="APIchunk22.html">s-s</a>
 <a href="APIchunk23.html">t-t</a>
-<a href="APIchunk24.html">u-v</a>
-<a href="APIchunk25.html">w-x</a>
+<a href="APIchunk24.html">u-w</a>
+<a href="APIchunk25.html">x-x</a>
 </h2><p><a href="bugs.html">Daniel Veillard</a></p></td></tr></table></td></tr></table></td></tr></table></td></tr></table></td></tr></table></body></html>