v2.2.1 changelog and quick start guide update

version v2.2.0

update changelog for v2.1.5

white status led for checking led

v2.1.4 changelog and update reference

v2.1.3 changelog update

free transpose fixes and improvements

fix MIDI semitone offset
Red led when transpose is out of valid range

v2.1.1 changelog update

increase midi velocity with factor 2

enable line in pass through instead of serial midi