use configured site domain to harvest tei-based rdf
utility method for generating local uris, to ensure consistent handling of trailing slashes in domain url
require rdflib 4.0 for now since 4.1 generates sparql parse errors when running data prep script
avoid duplicating site base path when generating local uris
disable unicode flags for normalize whitespace, to make python 2.6 compatible
fixture for testing local_uri utility method