[rfc] split out developer-oriented news

[Martin Pool]

I was wondering if we should split out the developer-oriented news
(API breaks, new recommendations etc) from the user release notes.
Most users will not want to read about it.  (I suppose it could give
them a clue if something breaks, but a web search would probably find
that too.)

It does mean there's one more thing people need to know to update, but
I think that is pretty easy.  The big thing is just knowing you need
to document api changes at all (and knowing what constitutes an api
change in Python.)

Orthogonally to this, I wonder if the user guide and perhaps also the
api change list would be better off just being grouped by major
release, rather than each beta.  So:

 bzr 2.4
   new features
   bugs fixed
   ...

  bzr 2.4.1

When 2.4 comes out is probably the main time people will read it, and
having the list of actual changes together would be better.

Martin