[MERGE] 1.14 formats

[Ian Clatworthy]

John Arbash Meinel wrote:

> It seems a shame to have a bunch more formats for this, when we are
> bringing out yet more, but certainly the content filtering is more
> stable than the brisbane code (as yet).

Projects where bzr scales fine need it now as well.

I'd like to suggest that we only bring out a *single* non-hidden
gc-chk-based format in 1.14 and that we ought to call it
1.14-development (instead of developmentX). I guess we'll still
have a hidden subtree one but let's not mention it.

1.14 would then ship with 3 new formats:

* 1.14 - the normal one
* 1.14-rich-root - for bzr-svn & bzr-git interop
* 1.14-development - a preview of our next-gen format for early adopters.

> BB:approve

Thanks. I'll wait till the other core developers have had a chance to
agree to releasing a 1.14 before merging.

Ian C.