LGTM from reading the code without testing. Thanks!
https://codereview.appspot.com/571180043/diff/565230043/input/regression/measure-spanner.ly File input/regression/measure-spanner.ly (right): https://codereview.appspot.com/571180043/diff/565230043/input/regression/measure-spanner.ly#newcode5 input/regression/measure-spanner.ly:5: Measure attached spanners can span single and multiple Shouldn't this be rather Measure-attached spanners ... ? https://codereview.appspot.com/571180043/diff/565230043/lily/measure-attached-spanner.cc File lily/measure-attached-spanner.cc (right): https://codereview.appspot.com/571180043/diff/565230043/lily/measure-attached-spanner.cc#newcode96 lily/measure-attached-spanner.cc:96: } The `}' is not aligned with `{'. Maybe incorrect use of tabs? https://codereview.appspot.com/571180043/diff/565230043/scm/define-music-types.scm File scm/define-music-types.scm (right): https://codereview.appspot.com/571180043/diff/565230043/scm/define-music-types.scm#newcode313 scm/define-music-types.scm:313: In case this a hard line break between `measure-' and `attached', please avoid it (and do the line break before `measure-'). https://codereview.appspot.com/571180043/diff/565230043/scm/scheme-engravers.scm File scm/scheme-engravers.scm (right): https://codereview.appspot.com/571180043/diff/565230043/scm/scheme-engravers.scm#newcode172 scm/scheme-engravers.scm:172: This engraver creates spanners bounded by the columns which start and s/which/that/ https://codereview.appspot.com/571180043/
