leds light up at boot

src/pwm.cpp

@@ -98,6 +98,7 @@ void Treppe::setup(){
     // see also lib/PCA9685-Arduin/PCA9685.h:204
     pwmController.init(PCA9685_PhaseBalancer_None);
     pwmController.setPWMFrequency(200);
+    pwmController.setAllChannelsPWM(idle_brightness);
 
     pinMode(SENSOR1, INPUT);
     pinMode(SENSOR2, INPUT);