automatic handling of staging

[Graham Percival]

James,

Patchy will now automatically push if the testing of staging works
well.  If it fails, you should see a message, and you can always
check ~/lilypond-automatic-compile-results/ (or whatever that dir
is called).

Let's not go with a cronjob quite yet, but if you could run it
twice a day, that would be great.  Hopefully it should require no
attention from you; if anything goes wrong, send an email to
-devel and the relevant developer should fix it.

- Graham