Disable voltage lpf by default

Filtering does more harm than good in voltage monitoring.
(alpha = 1 efficiently disables the filter.)

flix/power.ino

@@ -9,7 +9,7 @@
 #include "util.h"
 
 float voltage = NAN;
-LowPassFilter<float> voltageFilter(0.2);
+LowPassFilter<float> voltageFilter(1);
 int voltagePin = -1;
 float voltageScale = 2;