Prevent stuttering audio when CPU is busy with other tasks

[dheijl]

Sometimes, when the CPU is busy with other tasks (like running a build in Visual Studio), you can get some stuttering audio. This raises the thread priority a bit, preventing the stuttering, at least on my system.

[MX10-AC2N]

@sebastienwarin this commits are essential.. Thanks @dheijl for making releases before SWYH:master, I use this release and that work really better...