"what's new" document

[Martin Pool]

Ian added a "What's New in bzr 2.1" document and I've just updated
that for 2.2, and am in the middle of making one that will accumulate
changes for 2.3.
<http://doc.bazaar.canonical.com/bzr.2.2/en/whats-new/whats-new-in-2.2.html>

They provide a readable summary both for users and other participants
of what's changed - not many people are going to want to read through
all of the hundreds of NEWS entries for 2.2.  Instead in this document
we can pick out the most important changes, and group them together by
functional area rather than chronology.  It is complementary to NEWS
and I think we should keep both.  (Obviously there is some redundancy
but I think it's worth while.)

So when you change something notable, please consider adding it to
this document.  Then before actually doing the release we will check
and edit it.  "Notable" is fuzzy but it could mean a compatibility
change, a new feature, a performance improvement.  I think normally we
would not document bug fixes unless they were very major, because
they're not especially interesting except to users who were affected
by that bug.

This is similar to what Python does, amongst others.

Also, I think we should clarify how we handle NEWS across series.  My
proposal is:

 * a separate news file per series
 * don't copy bugs between series when they merge up; just say in the
header which previous-series releases were merged in.

-- 
Martin