ToDo: articulations, slurs and beams.
Simultaneous music wip.
More preparations for beams, slurs and articulations.
Articulations wip
More articulations and ornaments.
Fingering (technical notation).
ScaleDurations wip
This will not work yet for `\scaleDurations`,
because the fraction is not set in attribute `scaling`.
Addition to some of the comments.
Slurs
Staff changes
Lyrics wip
Lyrics wip
Better handling of sequence and simultaneous sections.
Restructuring BarMus classes.
Dynamics
Lyric stanzas
More structural adjustments.
Continuing stanza.
Lyrics wip.
Minor adjustments