Implemented the rdf::writer::implementation#make_raptor_term() method.
Implemented the rdf::writer::implementation#make_raptor_term() method.

bxshi/librdf,dirvine/librdf,datagraph/librdf,datagraph/librdf,bxshi/librdf,bxshi/librdf,dirvine/librdf,dirvine/librdf,datagraph/librdf