never live on master or staging

[Graham Percival]

Here's a tip that is making its way into the rewritten CG: don't
leave your lilypond repository as "master" or "staging".

To see the branch, add this:
  export PS1="address@hidden \w\$(__git_ps1)$ "
to your ~/.bashrc
(or just type it once to see what happens)

The general idea is that you should always see something like
  address@hidden ~/lilypond (doc-beaming)$ 
or
  address@hidden ~/lilypond (clang-warnings)$ 
or
  address@hidden ~/lilypond (scheme-2.0)$ 
or, if you're really not comfortable,
  address@hidden ~/lilypond (working)$ 

if you don't understand what I'm talking about, wait a week.  But
the __git_ps1 trick is so cool that I couldn't resist sending it
along right now, so that people "in the know" can start playing
with it immediately.

(I'm now working on a bash function that adds color to the
__git_ps1, so that master and staging are colored in red, to
remind myself to be careful when I'm on those branches)

Cheers,
- Graham