Dashed, variable-thickness slurs

[Carl D. Sorensen]

Dear LilyPond users,

I've posted a patch for approval that implements variable thickness dashed
and part-dashed, part-solid slurs.  I hope it will be fully implemented in
2.13.1.

As a preview, here's some slurs that were output by the new code.

Please let me know if these are acceptable, or if you'd like to see other
changes.

Thanks,

Carl

DashedSlurs.png
Description: DashedSlurs.png