IMPORTANT CHANGE: the RDF model is as of RDF 1.1! Rdf#Literal is now
concrete
moved the implicits for TypedLiteral and LangLiteral into Literal
adapted the test suite to the new model
reflected the new RDF model into banana-jena
reflected the new RDF model into banana-sesame.

This is relying on upcoming Sesame 2.8 series because of its very decent support for RDF1.1.
Return Some[X] for extractor when it cannot fail
prefix datatypes in JenaOps with __ just as a convention for saying this
is local (don't want to use modifiers)
Merge pull request #101 from w3c/rdf11

Make banana-rdf RDF1.1 happy