Realtime audio streaming example

[Meziu]

Because of size and other issues, I cut the audio-streaming example from ctru-rs. This weekend, I wanted to see if it was possible to write some working audio code using the exposed API, and the result is pretty satisfying! (the example is extremely rough, I just wanted to get it working for the most part)

You can check out my example at realtime-audio. It's pure Rust!

I may open a PR with some API changes in ndsp to solve some issues I found during this experiment. 😄