New plugin: merged-branches

[Jonathan Lange]

Hello all,

I just wrote a plugin that shows a list of local branches that are
safe to delete. It goes through the siblings of your trunk branch and
lists all those that have been merged and have no interesting local
changes.

Full details here: http://mumak.net/2008/03/18/ok-i-lied/
Code here: https://code.launchpad.net/~jml/+junk/merged-branches

Right now, it's good enough to solve my main problem, which is
gardening my branches directory. However, the code is very much a WIP,
and I would love to hear your feedback.

jml