Poor placement of scoop on downstem note

Windows 7, GIT commit: b00e0e5

1) new score
2) add a downstem note
3) add a "scoop" (last item on arpeggios/glissandi palette)

Result: scoop is poorly positioned

The scoop shouldn't cross the stem; it should look more like this:

Other chordlines are fine. BTW, there is also no space allocated for the scoop (or plop), but I've already addressed this in another PR.