updated git-cl

[Graham Percival]

there's an improved git-cl on my github account now:
https://github.com/gperciva/git-cl
Thanks to Lukasz Czerwinski, it tracks all lilypond patches with
the same base url.

http://codereview.appspot.com/search?base=http://git.savannah.gnu.org/gitweb/?p=lilypond.git/trunk/

All contributors are still urged to allow git-cl to make an issue
in the code.google.com issue tracker, but it's nice to have an
extra layer of security.  I suggest that everybody updates their
git-cl repo.

- Graham