Improved Winamp Visualizer by @x2nie

[0x5066]

This contains work started by @x2nie and continued by me.

There's a lot that's either broken and/or unfinished.

The main goal of this PR is to improve the visualizer of Webamp, bringing improvements to the Oscilloscope and Spectrum analyzer rendering.

Improving the Oscilloscope was achieved by taking the rendering code from the Equalizer and implanting it into the small visualizer box done by x2nie, improving the Spectrum Analyzer involved ditching the Web Audio API in favor of FFTNullsoft, providing a much more accurate representation of the audio. The spectrum analyzer code (at least for the thicker bands) was redone that makes use of reverse engineered code from Winamp 2.65, more specifically how the bar chunking is achieved as well as how the peaks are calculated (this is broken).