fixing ssn

I have just "fixed"  the dolce removal from ssn. The version we were looking at on webprotege had some errors of uncertain provenance, so I went back to SSN  as it was left by the XG here https://www.w3.org/2005/Incubator/ssn/ssnx/ssn.owl  (more commonly known as http://purl.oclc.org/NET/ssnx/ssn) and removed dolce all over again. I also changed the ssn namespace to the new W3c one, and the dolce one to the new one http://www.ontologydesignpatterns.org/ont/dul/DUL.owl, and added some  annotation comments to reflect this.

We now have, on github, a new folder sdw/ssn/ssn_separated which contains ssn.owl<https://github.com/w3c/sdw/blob/gh-pages/ssn/ssn_separated/ssn.owl> and        dul-alignment.owl<https://github.com/w3c/sdw/blob/gh-pages/ssn/ssn_separated/dul-alignment.owl>   . The latter imports dolce but the former does not.   If you look at the alignment ontology you can see that ssn has lost a few important things that now cannot be said at all and will need to be natively  rebuilt,  in addition to the constraints that dolce gave it.

There are also a good few "bugs" remaining - but these are all original ssn bugs. I am thinking of a few things in annotations (including stuff we already changed in the web-protégé version) and a lot of typos, and at least one place where some class is explicitly subclassed from owl;thing.

I plan to gradually work through those bugs - and will bring to the attention of the list anything that is not either already decided or for which there is some choice about what to do.

If anyone would like to give it a once-over in case I have done something stupid, please do.

--Kerry