TODO

H violin is whack!
M alt on play / stop button text when not connected to internet
H rhythm instruments
M bars missing on bass cleff (only when all notes are rests)
M mute all
M change things (volume) while playing

===

M adding new track doesn't count as dirty?  DIRTY state questionable. (on new song only?)
M repeat section
M play-along marker
M adjust volume / mute while running
M delete / copy / paste multiple notes
M dotting a tie rest converts it to a note
M mouse insert note
M note insert mode
M switch to BASS clef easily
M draw only bass clef if only bass notes


L not dirty after undo to origin
L pause--Transport toggle() function?
L sharps & flats are not in proper order to determine key
L allows sharp & flat on same note
L flats / sharps in proper order on accidentals area
L move from track-to-track using ctrl-keys (shift arrow up down)
L other time signatures
L optimization: rebar from changed location only

crescendo / decrescendo

Regularly:
=========
WINDOWS TEST

REARCHITECT / REDESIGN
======================
- invert notesequence and draw sequence?
  keep things 'rebarred' and derived the toneutils playback from that model


POLYFILL NEEDED on IE?

Was added to index.js:

if (!String.prototype.startsWith) {
  String.prototype.startsWith = function(searchString, position) {
    position = position || 0;
    return this.indexOf(searchString, position) === position;
  };
}


HOW TO?

In App.js InlineEdit:
  - validate func needs to return false if not valid but should also updated errorMessage...
    also, validation might want to involve an async action. How to resolve?

In NoteSequence.test.js, how to replace rebar() function temporarily with test double (jest.fn())

    // TODO: treble staff could be optional if the calcs for noteY
    //  when there's only a bass staff are adjusted
    // if (hasTrebleNotes(this.props.song, this.props.id)) { ... }