Fix audio blowups in \headphoneListener

This MR fixes audio blowups when using \headphoneListener at a sample rate other than 44.1kHz.

The LPF cutoff frequency calculation was using a mixture of SampleRate.ir and the value 44100. It was therefore possible under certain aziDeg and nfIndex combinations to end up with negative cutoff frequencies. Explosions ensued!

Firstly, I made the cutoff freq calculation based on the value 22050 (aka nyquist at 44.1kHz aka the limit of human hearing). I believe this is the code's original basic intent.

Second, I make significant formatting improvements. Some of these (moving the vars around) were necessary to allow the line:

nfIndex = nfIndex.clip(0.0, 1.0);

I believe it's absolutely necessary to clip nfIndex to 0.0 - 1.0 given how it is used.

The rest of the formatting was to remove the strange whitespacing and inconsistent indentation.