@context and shexc for ShapeResults

[ericprud]

It seems like low-haning fruit to have the results be available in RDF. We should at least do the engineering for that so that if we add it later, we have backwards-compatibility.

[gkellogg]

This could be done by making ShapeResults be serializable as JSON-LD, something like the following:

{
  "@context": "http://w3.org/ns/shex.jsonld",
  "@type": "ShapeResults",
  "results": {
    "http://example.com/node1": {
      "@type": "ShapeResult",
      "shape": "http://example.org/S",
      "result": true,
      "reason": "Just because"
  }
}

That requires a small update to the ShapeResults Type definition.

Same could be said for ShExError.