Laissez-vibrer ties attached to notes with cross-staff stems are cross-staff (issue...

Laissez-vibrer ties attached to notes with cross-staff stems are cross-staff (issue 1296)

This moves towards a model of cross staff where cross staff is defined as
"Any grob that is either not an element of a vertical axis group or whose
relative extent with respect to the vertical axis group of which it is an
element changes as a result of how far apart two or more vertical axis
groups are spaced."

The practical ramifications of this patch are that less programming errors
are triggered and there is less chance that early vertical alignment will
occur.