musical-tone v0.0.3

Usage:

const piano = makePiano(_ => {
  console.log('piano loaded');
});
const electricPiano = makeElectricPiano(_ => {
  console.log('electric piano loaded');
});
const drumSet = makeDrumSet(_ => {
  console.log('drum loaded');
});
document.getElementById('testing').onclick = _ => {
  piano.play(60, 0.9);
  piano.play(64);
}
document.getElementById('testing2').onclick = _ => {
  piano.stop(60);
  piano.stop(64);
}
document.getElementById('testing3').onclick = _ => {
  electricPiano.play(60, 0.9);
  electricPiano.play(64);
}
document.getElementById('testing4').onclick = _ => {
  electricPiano.stop(60);
  electricPiano.stop(64);
}
document.getElementById('testing5').onclick = _ => {
  drumSet.play(42);
  drumSet.play(46);
}
document.getElementById('testing6').onclick = _ => {
  drumSet.stop(42);
  drumSet.stop(46);
}