Begun transcription of music proposal from Vicki.
adding more music.
First pass through music schema. Left lots of TODOs.
Using sdo-music appspot
Another pass through, getting close to done.
Fix to 'producer' annotation.
more bugfixes.
andstr wasn't defined globally, so didn't work on enum.
Merge branch 'master' into sdo-music
Polish to music schema - copied in missing textual defs from doc,
added acks to mbz/mo, and a little more tidying.

Also attempting to use PublicationEvent instead of adding a custom type
for pair of place/time of a release.
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.
Tidying examples.
recordingOf is a property of a MusicRecording, not a MusicComposition.
Fixed the domainIncludes statement accordingly.
Marking this to show on MusicRelease, PublicationEvent.
Rationalizing 'producer' definition. Markup is now in one place, and the
domain is simply CreativeWork. Refined the description accordingly.
That'll teach me to commit without running the tests. Fixed bad markup.
An Organization can also be an arranger, now.
MuzicBrainz typo.