[Data-modeling] Proposed change for plays

[Bryan Cheung]

It's been proposed that we refactor plays to include written work.   
This would involve:

1) Migrating the data in the property /theater/play/playwright to / 
book/written_work/author. The property can then be deleted.
2) Migrating the data in the property /theater/play/date_written to / 
book/written_work/date_written. The property can then be deleted.
3) Add /book/written_work as an included type of /theater/play and co- 
type all existing instances of "play" with "written work"
4) Type all existing instances of /theater/playwright with /book/author
5) Delete the type /theater/playwright

Objections?  Will anybody's application break?

Thanks,
Bryan