define a minimal interface to the reasoner

[balhoff]

As an initial pass, we could define a Reasoner API in terms of only horned-owl, so that we don't expose internals of Whelk, which may change.

[cmungall]

I assume this would have a different signature from the OWLAPI one, specifically we'd want a way to retrieve superclass expressions? or would this be a layer on top in the analog of relation-graph?

[balhoff]

I do expect it to be different from the OWL API one. Superclass expressions would be more in the vein of relation-graph. Hopefully we can port that over as well once this project gets going again (soon). Should we keep relation-graph separate or fold it into this package?