[MERGE] Added PluginBranchConfig object, which allows a generalized mechanism for setting config options which travel along with the branch.

[John Arbash Meinel]

Monty Taylor wrote:
> Hey all,
> 
> Here's a patch to add a new Config object. I'm using in this in a couple
> of different plugins I'm using internally. It's based in large part on
> code from bzr-builddeb, and hopefully just allows that to happen in a
> general manner.
> 
> I'd love feedback on this... and also any tips on how we might want to
> write unit tests...
> 
> Monty
> 
> 

BB:resubmit

At a minimum it needs tests before it can be merged. And my other 
message includes some points to discuss.

John
=:->