Design notes for next values iteration

[Dan Smith]

Following up on John's mail, here are some detailed notes about the design choices for "U types", and the concrete proposal we settled on last week.

http://cr.openjdk.java.net/~dlsmith/values-notes.html

John may have raised additional points I didn't cover in this document. I'll do another review of his mail and make any needed updates; or feel free to call them out. :-)

—Dan