[rewrite xml export] basic handling of notes and rests
[rewrite xml export] bar attributes
[rewrite xml export] accidentals
[rewrite xml export] file structure
[rewrite xml export] inner structure
[rewrite xml export] scaler/tuplets
[rewrite xml export] scaling
[rewrite xml export] chords
[rewrite xml export] repeats
[rewrite xml export] voices
[rewrite xml export] grace notes and pianostaff/grandstaff
[rewrite xml export] VoiceSeparator construct
[rewrite xml export] tremolos
[rewrite xml export] instrument name
[rewrite xml export] removing obsolete code
[rewrite xml export] more code cleanup
[rewrite xml export] multimeasure rests
[rewrite xml export] more bug fixes
[rewrite xml export] more stability
Better handling of skips