Provide a better definition of edge

[cmungall]

This is quite minimal: https://cmungall.github.io/knowledge-graph-change-language/Edge/

The description of edge should be improved, as well as the mapping to OWL

Mapping to OWL

For v1 we can have the simple mapping:

• A subClassOf B <==> Edge(subject=A, predicate=subClassOf, object=B)
• A subClassOf P some B <==> Edge(subject=A, predicate=P, object=B)

For v2 we extend this, with an additional owlinterpretation edge property, as per owl star. See https://github.com/cmungall/owlstar/blob/master/owlstar.ttl.

For example:

• A subClassOf P only B <==> Edge(subject=A, predicate=P, object=B, interpretation=allValuesFrom)