[rfc] bzr-colo into core

[Martin Pool]

Congratulations, and best wishes for your child.

I think bzr-colo has been a great experiment.  My first mail was a bit
misleadingly titled: I don't intend to bring it in just exactly as it
is, and certainly not under the prefixed names.  But I do think now is
a good time to think about what we ought to learn from the experiment,
and how we can make the benefits more widely available.

I agree with your particular points: we still need to make it easy to
have separate workspaces; repository references (see John's recent
mail) could be good; we don't need to give up anything you can do
now(*); and we should be more explicit and clear about the components
underneath.

(*) We can think about deprecating arrangements that people might
arrive in by accident, or that add complexity without enough real
benefit.

Martin