Added new items & reworded old ones.
Item for eg/basics fixes.
Improved TODO item wording.
A Single stroke roll is defined in 32nd notes.
Note that we are using MIDI::Simple (as opposed to be a subclass). Add commented debug code.
Simplify single_stroke_roll() and add single_stroke_four().
Specify phrases number. Loop over known rudiments. Comment code paragraphs.