Added support for the LSDG_LIGHTS_SERIAL env var, to let us set the serial device without changing the config file.
Added support for updating 'thresholds' in the per-song JSON file when generating the FFT output. Also, store 'msPerLine' so we know how fast to play back the CSV.
Fixed usage of 'vals' instead of 'lightStates', simplified timestamp check code, added support for song.msPerLine, and fixed jshint issue.
Added scripts/testserial.py, which opens a pseudo-TTY, and runs the Node.js code using that as the serial port; displays the light states graphically.
Clear fake light display on exit.
Alternate way of calculating buckets; take median of amplitudes instead of average.