lein2 outline

* lein2
** new repl
   - completion
   - readline
   - nrepl-backed; common tooling
** profiles
   - no more plugins
   - dev, user
   - with-profiles
** aliases
   - offline, -U support via aliases
   - partial aliases
** pomegranate
** newnew
** middleware
** signing, verify
* upgrading
** precate
** project/lein isolation
** min-lein-version
* internals
** eval-in-project
** tasks as functions
** build as a function of project.clj/args, repos as dynamic scope