Showing variations using ossia staves

[goplayerjuggler]

I would love to be able to use abcjs to render ossia.

Other ABC engines (abcm2ps and C Hume's tool) seem to do a good job on this sample - an extract from one of JS Bach's WTC fugues.

At the moment there seem to be multiple issues in how abcjs renders this sample.

[paulrosen]

Interesting example. Yes, I see multiple issues.

I'd love to get some help with them. I'll work on them, but it will be slow since I'm in the middle of a few other improvements.