Re: renaming "vertical spacing inside systems" props

[Mark Polesky]

Keith E OHara wrote:
> I had imagined you would simultaneously change
>        staff-affinity  (UP / DOWN / CENTER)
> to    reference-direction (UP / DOWN / CENTER)
> so we can remember that this direction tells us which
> staff is which between referencestaff and oppositestaff.

I think staff-affinity is more informative than
reference-direction.

> The closest I could find to a flaw was that
> nonstaff-unrelatedstaff-spacing also determines the space
> between an UP nonstaff and a DOWN nonstaff (if there is no
> CENTER nonstaff between them)...

I *think* that's just a case of stretching to prevent
collisions.  Does the same happen when all the
'stretchability and 'padding keys are set to 0?  If yes,
please post a minimal example.

- Mark