Implement panning and equalizer low level functionality

[terribleplan]

There is support for PannerNode which lets you do the balance, as well as BiquadFilterNode which lets you build an eq.

I may look into doing this as I've been looking for an excuse to really use some of the web audio stuff.

[terribleplan]

Also may look into using the GainNode for real volume control (iOS is broken?)

[captbaritone]

👍 If you want somebody else to do the UI, let me know.

[captbaritone]

I'd love to start with the balance before we get into the equalizer, if that's possible.

[captbaritone]

@Cqoicebordel shared this relevant StackOverflow answer: http://stackoverflow.com/questions/12738056/creating-a-10-band-equalizer-using-web-audio-api

[captbaritone]

Here's a useful example for the visual portion: http://webaudioapi.com/samples/frequency-response/

[captbaritone]

7b6d3f4 fixes the balance part. I'll create a separate issue for the EQ functionality and copy the relevant information.

[captbaritone]

New issue for EQ functionality here: #75