AFG Harmonic Animation inputs

So, I just noticed this, otherwise I would have put this in the video,
but the PWM +/- and PPM +/- input pairs in the AFG are normalled. For
example, if you apply some voltage to PWM- in, it will also apply to
PWM+. Patching PWM+ then breaks the normalization.

Pretty handy and a great feature!
Kudos Mike!