allow multiple classes and/or class expressions in some CSV fields

[stuckyb]

Add support for defining multiple equivalency axioms, multiple subclass of axioms, etc. for a class, and possibly also multiple domains, ranges, or disjointness axioms for properties. These would require supporting multiple Manchester Syntax class expressions in a single CSV cell.

[stuckyb]

Multiple subclass of and/or equivalency axioms are now supported.

[stuckyb]

Multiple classes and/or class expressions are now supported in all entity-specific fields where it makes sense to do so.

[ramonawalls]

@stuckyb What is the syntax for doing this? Can you provide an example? @megbalk and I have tried a bunch of things but haven't hit on the correct way yet.