Made Literal<->python objects and XSD types more in line with SPARQL/Turtle/N3. \nFixes issue 183.\nFixes issue 203.\n
Made Literal<->python objects and XSD types more in line with SPARQL/Turtle/N3. \nFixes issue 183.\nFixes issue 203.\n

Letractively/rdflib,Letractively/rdflib,Letractively/rdflib