* audio: Overhauled. New Mixer, new decoders, and added proper support for soundData as a static source.

 - avoids cutting sounds before they finish playing
 - cleans up memory for sources
 - even closes file handles!!

* Rename ogg vorbis decoder functions to decOgg_* to match with decWav_ API

* audio: fix WAVE audio corruption at end of sample

Main issue is that some RIFF WAV files have additional non-audio chunks at the end of the file, for meta data. We were mixing this into the audio buffer, causing noise.