* robustify Beam (in case of no stems, 32nd notes)
+ * fix [c8 c16 c16] (mustn't slope)
+
+ * fix silly " "2*12 a4 (=4*12) sticky plet
+
* check for groff / troff/ nroff et
* latex quirk?
* add to MIDI output:
- tempo change
+ - ornaments (and trills?)
- repeat
- slurs
- - dynamics etc.
+ - accents
+ - dynamics
+ - account for rhythmic position in measure
+ - etc.
* grace notes
- make separate class for Grace_*_engravers