Pulseaudio: rewrite the pa backend with the async api

The default async api allow us to set some latency options. The old one (simple API) was the lazy way to go for usual audio where latency doesn't matter.

This also streams audio, so it should be a bit faster then the old one.
Atomic Stores / Loads
Merge pull request #20 from degasus/pulseaudioRewrite

Pulseaudio: rewrite the pa backend with the async api