Add work json-ld serialization, as well as ISWCs and ISRCs.
Add JSON-LD sameAs links for applicable URL relationships and ISNI codes.
Merge remote-tracking branch 'bitbucket/jsonld-works-isrcs' into beta

* bitbucket/jsonld-works-isrcs:
  Add work json-ld serialization, as well as ISWCs and ISRCs.
Merge remote-tracking branch 'bitbucket/jsonld-sameas-urls' into beta

* bitbucket/jsonld-sameas-urls:
  Add JSON-LD sameAs links for applicable URL relationships and ISNI codes.