Initial work on CDATA section output. If I manually populate the set of
cdata section elements, everything looks great, so I just need to hook that up.
Added operator< to QName so I pop it in a std::set.
fixed internal qname resolution - 2.4 says unprefixed names are not in the default namespace
fixed xsl:element - unprefixed names, when no namespace uri is supplied are in teh default namespace
