Support new properties

[PR0CK0]

First off, @nicholascar, love your project. It's amazing for demoing ontologies to clients. Anyhow, there are a few commonly-used properties that are not supported and would be nice to see for more metadata. Not sure if I can just edit the properties .py file myself and have it work, because I'm using CLI. If I can do that, let me know and I'd be happy to merge request.

Annotation Properties: skos:prefLabel skos:altLabel skos:editorialNote rdfs:seeAlso (https://github.com/RDFLib/pyLODE/issues/174)

I use these a lot when describing the ontology itself: dct:subject dct:audience dct:format dct:language

Other: owl:equivalentProperty (https://github.com/RDFLib/pyLODE/issues/175)