Minor syntactic clean-up and new Argonaut type class instance.
Updates.
Some messy fixes.
Added Argonaut stuff.
Updated JSON-LD library version and specified SBT version.
Merged.
Added Sesame RDF-JSON implementation.
Use plain old default Jena graphs.
Use older union.
Switched to new Jena operations trait.
Some minor clean-up and version changes.