New branch for elpa contents

[Chong Yidong]

Following the discussion on opening up the package repository for Emacs
devs, I've made a new branch which you can check out with

  bzr branch bzr+ssh://address@hidden/emacs/elpa elpa/

Creating a local package repository from a checkout of this branch is
not implemented yet.  Neither is the infrastructure for updating the
actual contents of elpa.gnu.org by merging in from this branch.  Help
welcome.

(ttz: I made this a brand new repo; I didn't touch the existing
elpa.gnu.org setup, which we'll keep running independently until this
newer setup is working properly.)