GitLab

* Night mode is still available when pressing the flash button
* "led 0" or "led 1" should now be used as commands instead of
"night_mode"

* The 'int' return signature and the comment
'Returns the number of remaining leds' sounds like the
function would return its current countdown state.
However, it only returns the number of remaining
leds after the button was released. Thus change
the type to 'bool' and return 'true' after a
successful countdown

* Do not use 1 as return value for night mode,
because it is ambigous. Return 'false' instead.

LED Effects : small refactor, to allow breathing to be disabled (remove MIN_BRIGHTNESS or set it to MAX_BRIGHTNESS).