[Denemo-devel] Fixed long standing wrong stems bug.

[Richard Shann]

I've fixed the long standing bug in the display when you go staffup/down
where the clefs are different in the two staffs.
The problem is the draw routine side-effecting the cursorclef variable.
I've fixed a similar problem with changing movements. These fixes need
doing properly (rather than just invoking the draw), but at least the
problem is understood now. Please report any other cases where the
stemming goes bad (in the display - it does not affect the print-out).
Richard