Simon - getButtonPress

///////////////////////////////////////////////////////////////////////////////
uint8_t getButtonPress() {
  for (int b=0; b<4; b++) {
    for (int p=0; p<2; p++) {
      if (CircuitPlayground.readCap(simonButton[b].capPad[p]) > CAP_THRESHOLD) {
        indicateButton(b, DEBOUNCE);
        return b;
      }
    }
  }
  return NO_BUTTON;
}