Syndetics: start switch to XML::LibXML to parse results

Syndetics: start switch to XML::LibXML to parse results

XML::Simple doesn't handle mixed content, which is a
problem because reviews provided by Syndetics sometimes
contain HTML tags.  Furthermore, it's often easier to write
XPath to extract bits of an XML document than trying
to play with XML::Simple's options.

Signed-off-by: Galen Charlton <galen.charlton@liblime.com>