They are really specific to 3/4 beaming only. 3/4 has special standards
that don't apply to other music. beamHalfMeasure and beamFullMeasure, just
like the context property descriptions say, apply only to 3/4.
I thought about adding the 3/4 to the property name, but it seemed to
needlessly lengthen the name. In other time signatures, you can choose
your behavior by setting beamExceptions.