[rfc] 'bzr reconfigure --stacked-on/--no-stacked'

[Martin Pool]

There is at present no user-accessible way to change a branch between
being stacked on another repository, and containing all its history in
its own repository.  I think there should be.  It would be useful in
general, and in particular as a workaround if people are having
trouble with stacking on Launchpad, which suggests that setting for
some projects.  Basically this is just to expose the
Branch.set_stacked_on() call.

I think this belongs in 'reconfigure'; it shouldn't be invoked often
enough to need its own command.

-- 
Martin <http://launchpad.net/~mbp/>