reverted contextStringTuning again

[Graham Percival]

Hi David,

I'm sorry, but I still cannot build git master from scratch when I
have your contextStringtuning commit pushed.  Please discuss the
situation on lilypond-devel, and put an updated patch on Rietveld
so that James can test the build.  I cannot leave git master in an
uncompilable state.

Please note that running "make doc" a second time is *BROKEN* and
should never be trusted.  The *ONLY* way to accurately+confidently
test whether a patch will work or not is to completely remove your
build directory and compile from scratch (i.e. starting from
../configure).  See for example
http://code.google.com/p/lilypond/issues/detail?id=1852
I think that the "touch" trick is sufficient to work around 1852,
but if you did that and it still worked for you, then evidently
that's not a reliable workaround.


I've added
  input/regression/context-string-tuning.ly
which makes sure that git master can compile with the current
function definition.  Somebody might want to make a better test /
better texidoc, but at the moment I just want to have something in
there.  This function was not previously tested.

Cheers,
- Graham