Allow music identifiers in \addlyrics (no need for braces any more) (issue2740044)

[v . villenave]

Hi Reinhold,

this patch looks awesome; I can't believe I've missed it!  Thanks to
Nathan for digging it up.

Although it's not my call, I find it pretty harmless and straightforward
and I hope you'll merge it soon.  This will make things easier for a
*lot* of new users!

Cheers,
Valentin.


http://codereview.appspot.com/2740044/diff/4001/input/regression/newaddlyrics-music-identifiers.ly
File input/regression/newaddlyrics-music-identifiers.ly (right):

http://codereview.appspot.com/2740044/diff/4001/input/regression/newaddlyrics-music-identifiers.ly#newcode14
input/regression/newaddlyrics-music-identifiers.ly:14: % This didn't
work so far:
Do we really need this level of verbosity in the regtest comments?
Regardless of what used not to work in the past, I'd just say "Both
syntaxes below should produce the same result."

http://codereview.appspot.com/2740044/