associate branch with source package

I think a branch should be associated to a product OR a source package.

A package branch is different in content and purpose from an upstream branch, and is targeted to different people. The distinction is a bit similar to how upstream bugtasks and distro bugtasks are different classes because that are related to the same object (bug, product) in different contexts (upstream, distro).

On trunk, as it stands:
  - you can perform bzr operations on personal package branches (e.g. ~jml/ubuntu/jaunty/bzr/make-it-fast)
  - you can mark these branches as being the official branches for a pocket of a source package.

Well, you could if we hadn't got the feature turned off in a config file while we're getting the UI ready.

This week, I'll start talk about flipping the switch so you can push to production, rather than staging. That way the branches can be there even if the UI lags a bit.

I'll have been and will be filing bugs with the tag package-branches for the details of the work that's left. I'll only be filing them as they come to mind though.

You can create source package branches on production now.

There are many open bugs, but the core of the work is essentially done, so this particular bug task has served its purpose.

See https://bugs.edge.launchpad.net/launchpad-bazaar/+bugs?field.tag=package-branches for the open bugs I mentioned.