footswitch can now be used as a sustain pedal
when not in unison and not arpeggiating
adsr: exponential decay/release curve adjustment
slightly less abrupt release end, still not perfect because of how the VCA behaves.
Set RW in alpha version name
Added deadband for pitch wheel
Add dead band for panel zero centered pots
Consolidate deadband calculations to one function
Add guard at top and bottom of range when deadbanding

* This is important to get true intervals for the pitch wheel, because
  the analog voltage from the wheel as seen by the ADC is not the
  whole available range, leading to the resulting output from the ADC
  not to cover the whole 0..65535 range.