NR 2.1 Vocal music

[Trevor Daniels]

Graham

I've just pushed a patch to NR 2.1 Vocal music which provides a 
first draft for the last of the blank sections marked TBC ("To Be 
Completed").  I believe it's now in a much better shape than it was, 
even though much of the chapter is in "first draft" state.

Next up are the 19 TODOs, and I'd like to work through them before 
inviting a review of the whole chapter, although if you or anyone 
else wishes to comment on the work so far I'd be happy with that 
too.

Trevor