The old NEWS file was getting long and difficult to maintain. To help

with both reading and writing the release notes, this change has moved

them all to the new place.
The content of the release notes haven't changed, with the exception

that references and ReST roles have been added where appropriate, to

just help take advantage of the fact that they're now being rendered to

HTML.

Generated the docs. Went through every single release notes page to make

sure things looked correct.