replacement git-cl

[Graham Percival]

Please use
  https://github.com/gperciva/git-cl
instead of the current git-cl.  To configure, add a file called
  google.login
to your lilypond srcdir, in the format
username
password

This updated git-cl will:
- create an issue with Patch-new to code.google.com, including a
  link to your rietveld issue of course
or
- update an existing issue with your Patch-new link if you include
  "fix xyz" or "issue xyz" in your patch description

There will still be rough edges, but the projecthosting_upload.py
part of the new git-cl is pretty small and should be easy to
patch.  Problem reports and patches are most welcome.

Once this script is fully tested and working, it will relieve a
lot of our current frustrations.  Please switch to it -- even if
there's a problem with the new parts of the script, the original
behavior of the rietveld upload is completely unchanged, so you
lose nothing!

Cheers,
- Graham