After pressing the "Flash" button a long time to initiate calibration and releasing it after the finished countdown, the ampel sometimes switches to night mode.
This happens if the button is still pressed during the next call of checkFlashButton() and released < 300 ms after that.
Therefore:
- Disable button polling during calibration.
- Clarify blocking nature of
led_effects::countdownToZero()
I was pretty confused how checkFlashButton() and countdownToZero interact and
think that it is clearer now. I know there is a 'loss' of functionality in the sense
that it is not possible to check for partially-finished countdowns. But this
functionality was not used.
Closes #4 (closed).