Working on music examples.
Renamed my proposed property for hasReleaseRegion from "releasedAt"
to "releaseEvent" since we already have "releaseDate" in
http://schema.org/releaseDate (on Product, not CreativeWork, awkwardly).
Lots of music examples - thanks Vicki!

I've syntax checked and fixed this with jsonlint, but not
scrutinised the triples.

Tweaks: 'iswc' was renamed 'iswcCode'.

Also trying to avoid hasReleaseRegion + CreativeWorkReleaseRegion
being added, so for now example recycles PublicationEvent type via
a releaseEvent property.