Add git-reup and friends

git_nav_downstream.py

 #!/usr/bin/env python
 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 Checks out a downstream branch from the currently checked out branch. If there
 is more than one downstream branch, then this script will prompt you to select
 which branch.
 """
+
 import sys
 
 from git_common import current_branch, branches, upstream, run, hash_one
 
 
 def main(argv):
   assert len(argv) == 1, "No arguments expected"
   upfn = upstream
   cur = current_branch()
   if cur == 'HEAD':
@@ skipping 18 matching lines @@
       r = raw_input("Selection (0-%d)[0]: " % high).strip() or '0'
       if not r.isdigit() or (0 > int(r) > high):
         print "Invalid choice."
       else:
         run('checkout', downstreams[int(r)])
         break
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))