2 - Rational for time measurement
4 - directionalspanner/textspanner
9 - grouping code: LilyPond can set advanced multibeams.
12 - robust Staff_commands
15 - robust Input_commands
16 - merged Vertical_/Horizontal music
17 - PARTIALs with duration
18 - modularized lexer: multiple runs
21 - notenames configurable
33 - Horizontal/Vertical music