Add standard shape map

[balhoff]

I think we should add a top level shape map that any of the processors (Python, Java, Scala) could use to make model checking more consistent. I'm not exactly sure what shape map is being used inside the Python tester right now.

We will still need to inject subClassOf axioms before running, but then I think we could use a single shape map across applications.

[balhoff]

Can't find any recommended file extension for shape maps. (Update—I see .shapeMap in the Shaclex examples)

[balhoff]

I made a start on this, but I see we have a problem. Since we want to specify nodes by their types, but we want only one asserted type in the file, the query shape map format is a little too limited for us. I started off with patterns like this (which don't work because we aren't propagating all the inferred types to instances):

{ FOCUS a <http://purl.obolibrary.org/obo/GO_0003674> } @ <http://purl.obolibrary.org/obo/go/shapes/MolecularFunction>

After injecting the subclass axioms, we need two hops to match the desired nodes:

{ FOCUS a/rdfs:subClassOf <http://purl.obolibrary.org/obo/GO_0003674> } @ <http://purl.obolibrary.org/obo/go/shapes/MolecularFunction>

The Validating RDF book mentions that Wikidata is embedding SPARQL in shape maps, which would work much better.

[balhoff]

I added an initial shape map using the SPARQL syntax in #71. This format is supported by Shaclex and Shex.js, according to shexSpec/shex#93.