2 - Move breaking stuff into a separate class Break_algorithm
3 - dependencies for Staff_elem's
9 - Rational for time measurement
10 - updated doco to .pod
11 - directionalspanner/textspanner
16 - grouping code: LilyPond can set advanced multibeams.
19 - robust Staff_commands
22 - robust Input_commands
23 - merged Vertical_/Horizontal music
24 - PARTIALs with duration
25 - modularized lexer: multiple runs
28 - notenames configurable
40 - Horizontal/Vertical music