For update commands, pass parent and child concepts to php

Only for update, since we don't seem to need it for the other commands yet.
Use parent and child concepts from JavaScript instead of relation sig

This way, if the modified concept is a specialization, we use the specialized concept for addAtomToConcept, rather than the general concept that is in the relation signature, thus causing editUpdate to work correctly for narrowed relations.
Allow editing also on narrowed relations + Cleanup