LilyPond Contributors List update

[Peekay Ex]

Ian,

I've just updated a few of the newer contributors to LilyPond and
added them to ..\Documentation\included\authors.itexi.

I saw that you are still listed on 'previous contributors' and assumed
you had git push access I haven't added you because of that but
thought you might like to put yourself in the appropriate place.

Regards

-- 
--
James