Lyrics to cue notes

[Carl D. Sorensen]

Having read Reinhold's list, I thought it might be useful to try to attack
some of these things.  I looked briefly at the lyrics to cue voices and the
lyrics to partcombined music.  I haven't got any brilliant ideas yet, but
I'm starting to noodle on it.  There's a note in lyric-combine-iterator.cc
that suggests it would be better to fundamentally adjust the working of
lyricsto.  I'm thinking about that, but still trying to get my head around
the current operation.

As a quick workaround on putting lyrics to cue notes, I thought it might be
possible to make \lyricsto work with CueVoice contexts as well as Voice
contexts.  Before I jump into trying this, I thought I'd ask the core
developers if there are any limitations of which I'm unaware that would make
this approach unlikely.  So, does anybody think that add CueVoice as well as
Voice to lyricsto would work (or not)?

Thanks,

Carl