Small file improvements

[braheezy]

While working with small (less than 1s) and mono channel WAV files, I noticed several bugs in how the player handles this.

Of note:

• Files with a bit depth lower than 16 don't encode well to QOA format. The WAV decoding logic produces no audio when stuffed into QOA bits. I tried something where I scaled the 8bit number to the 16bit range, and while this did produce audio, it was high-pitched and incorrect.
• The oto audio player only allows one audio context to be created and it cannot be changed after the fact. At context creation time, the channel number is set. 2 is a good default, but mono files will be played twice as fast. So I made updates to the QOA library Reader to duplicate mono data into stereo channels and this seems to work, the audio sounds good.