Added a "See also" section with some external references.

Doc/lib/libxmllib.tex

@@ -227,6 +227,18 @@ implementation does nothing.
 \end{methoddesc}
 
 
+\begin{seealso}
+  \seetext{The Python XML Topic Guide provides a great deal of information
+           on using XML from Python and links to other sources of information
+           on XML.  It's located on the Web at
+           \url{http://www.python.org/topics/xml/}.}
+
+  \seetext{The Python XML Special Interest Group is developing substantial
+           support for processing XML from Python.  See
+           \url{http://www.python.org/sigs/xml-sig/} for more information.}
+\end{seealso}
+
+
 \subsection{XML Namespaces \label{xml-namespace}}
 
 This module has support for XML namespaces as defined in the XML