Musicdiff

Use a new MEI parser from converter21. Compare grace notes (including whether they are accented or unaccented). General bug fixes.

Add support for comparison of ArpeggioMark, ArpeggioMarkSpanner, and RepeatBracket.

Add support for comparison of lyrics within AllObjects (default diff) and AllObjectsWithStyle.

Added diff of non-notes (clefs, etc), as well as detailed diff including style (text fonts, stem direction, note color, etc).
New DetailLevel parameter: GeneralNotesOnly (like v1), AllObjects (default), AllObjectsWithStyle (notice detailed differences)

Initial public release.