label:Frog for issue tracker

[Graham Percival]

I've added a label:Frog for the google issue tracker; this indicates a
task suitable for a new contributor.  I'm kind-of bending the
definition of "Frog", since a bunch of the issues are documentation
tasks... but then again, I figured that since the main developers get
their hands dirty with the docs, there's nothing wrong with
encouraging the Frogs to do it, too.

I haven't looked at any Defect, Collision, or Enhancement issues.

http://code.google.com/p/lilypond/issues/list?can=2&q=label:Frog&mode=grid&y=Priority&x=Type&cells=ids
(link has been added to the CG)

Cheers,
- Graham