New sync'd branch

[Stefan Monnier <monnier@iro.umontreal.ca>]

We'd like to have a new release in the first half of next year with some
new features.  Given the short time, the new features need to be
non-intrusive, like new packages.

Until now, we've had 2 active branches: the EMACS_23_1 and the trunk,
where the first is limited to bugfixes (and mostly unused, really), and
the second is aiming to become the next release.

But two things make me think we should change this arrangement:
1- the desire and need to plan for Emacs-24: if we want to keep
   releasing regularly, we need to have 2 active branches, one for
   short-term localized improvements, and the other for longer
   term changes.
2- the fact that Emacs-23.1 seems not to suffer from any serious
   problems that would call for a quick new release from the
   EMACS_23_1 branch.

So I believe we should create a new branch EMACS_23 which will play the
role currently played by the trunk, so the trunk can now be open to more
experimental development (bidi, cpp->autoconf conversion, lexbind, ...),
targetted for Emacs-24.

There are some problem with this:
- Changes on the 23 branch need to be sync'd to the trunk.  As long as
  we haven't switched to Bzr, that means we need Miles to do the sync
  for us.  Miles, could you do that?
- People installing changes need to carefully choose whether to install
  it on the 23 branch (from where it will be sync'd to the "24 branch"
  aka "trunk"), or on the trunk.  Basically, the most important aspect
  is that any bugfix which makes sense on the 23 branch need to be
  installed on the 23 branch rather than on the trunk.
- The 23 branch will not see as much testing any more.  So we need to be
  more conservative on what can go there.  And we need to make
  a conscious effort to try and use the 23 branch on a regular basis.
  Maybe if the trunk is sufficiently unstable, this will not be
  too problematic.

What do you all think about this?


        Stefan