Major refactor of parsing and serializing. SPARQL queries work, but lots
of other stuff probably doesn't.
preferred_media_types now on Endpoint constructor on all StoreViews
Added priority to srj so srx is preferred when all is otherwise equal.
Removed unused code.
Tidying up SPARQL views.
Got CannedQueryView working again.
rdflib parsers can now have args/kwargs passed through.
StreamingParser.get() now binds namespaces for graph results.
StreamingParser.format_type added to tell between graph and SR parsers.
Tidied whitespace.
Removed unused imports
Fixed ==/= mix-up
RDFlib parsers can only be called once.