get debugging information from XML::LibXML

 XML::LibXML::Debugging is a Perl library which adds a couple of
 additional methods to XML::LibXML::Node objects which are mostly aimed
 at helping figure out what's going on with the DOM's namespaces and
 structure. "toClarkML" produces a string of XML-like markup with
 explicit namespaces. The following XML:
 .
      <foo xmlns="http://example.com/1"
           xmlns:bar="http://example.com/2"
           bar:baz="quux" />
 .
 Might be represented as:
 .
      <{http://example.com/1}foo
           {http://www.w3.org/2000/xmlns/}XMLNS="http://example.com/1"
           {http://www.w3.org/2000/xmlns/}bar="http://example.com/2"
           {http://example.com/2}baz="quux" />
 .
 Another method "toDebuggingHash" returns a hashref suitable for dumping
 using Data::Dumper.