Cleanup version

Minor problems set, some cleanup removing unnecessary things, and updated the initial context

Updated to upcoming RDFLIB 5.0

RDFLib 5.0 will remove the rdfa parser from the core distribution; the idea is that this repo will be the only one used as, e.g., a plugin to rdflib.

pyRdfa: RDFa 1.1 extractor software for HTML5 and XML

citable-release

Changed the warning text