[ssn] equivalence axioms to relate the old ssn to the new ssn.

SSN-ers,
I have built a small ontology to relate the classes and properties of ssn in its new namespace  (http://www.w3.org/ns/ssn/) to the classes and properties of the old  (SSN-XG) ssn in its old namespace .  The intention of this is that it becomes a part of the normative ssn but is served in a different ontology file so that it does not need to be loaded up in order to use the new ssn. However, it (hopefully) will enable us to use implementations of the old ssn as proof of implementations of the new ssn (where concepts by all of intension ,  rdfs: comment description,  and the suffix part of their names have not changed).

Please see it here https://github.com/w3c/sdw/blob/gh-pages/ssn/ssn_separated/ssn_equivalences.owl  I would like to include this in the FPWD so that our plan for implementation evidence can be tested before it is too late. I will also get it into the rec document, I hope.

Any comments gratefully received.
-Kerry