Release of libxml2-2.9.1

* configure.in: bumped version
* doc/*: updated the symbols file and regenerated
diff --git a/doc/APIchunk26.html b/doc/APIchunk26.html
index 50e814f..17666cf 100644
--- a/doc/APIchunk26.html
+++ b/doc/APIchunk26.html
@@ -298,6 +298,7 @@
 </dd><dt>void</dt><dd><a href="html/libxml-hash.html#XML_CAST_FPTR">XML_CAST_FPTR</a><br />
 <a href="html/libxml-parser.html#xmlSAXParseFileWithData">xmlSAXParseFileWithData</a><br />
 <a href="html/libxml-parser.html#xmlSAXParseMemoryWithData">xmlSAXParseMemoryWithData</a><br />
+</dd><dt>volume</dt><dd><a href="html/libxml-parser.html#_xmlParserCtxt">_xmlParserCtxt</a><br />
 </dd></dl><h2 align="center"><a href="APIchunk0.html">A-B</a>
 <a href="APIchunk1.html">C-C</a>
 <a href="APIchunk2.html">D-E</a>