I am working on a piece with no time signature or bar engraver. However, I do want to
have a few bars here and there, and a bar to end the piece. I am using the SATB vocal
score on this page: http://lilypond.org/doc/v2.12/Documentation/user/lilypond-
learning/Vocal-ensembles#Vocal-ensembles
Is there a tweak for adjusting when the bar engraver works or not?