Document mapping to OWL

[cmungall]

This could either be in this library, or it could be in the minerva-json payload documentation.

Minimally a key:

• svf ==> 'SomeValuesFrom'
• intersection ==> IntersectionOf
• union ==> UnionOf

Ideally each constructor would have jsdocs linking to relevant section in:
http://www.w3.org/TR/owl2-syntax/#

Also: document profile, which is currently a subset of EL++ plus unions.

Also some GO-centric examples might be useful

[cmungall]

cc @dosumis, the json swapped back and forth between moctua and minerva may attain a more general purpose as our standard json for class expressions

[dosumis]

OK. Would be v.interested to see full specs.