Hiding a stave for a specific movement

Currently the most strasightforward way to do that would be to have the movements in separate files. But it's possible with some effort to do in one file as well. You'd have to add some sort of token element (some people use text that is colored white) to one measure of each otherwise-empty system in the movement where you want the empty staves to show.

This is something we'd definitely like to improve in the future.