A utility class to help deal with RDF namespaces (converting between short (qualified) names and full URLs for XML namespaces.
my $ns = RDF::Simple::NS->new;
$ns->lookup('foaf'=>'http://xmlns.com/foaf/0.1/');
$ns->lookup('short name'=>'http://full.path.to/namespace#');
Add an alias for a namespace (this will be used in the serialisation)
