[108] Autoplagiarism

I don't have enough time to show exactly how it works, or what it looks like when it's working, but I made a more lightweight, standalone version of kmixerAsync.

It's about an eighth the size of kmixer+kmixerAsync, while having most of Async's features.

I also started learning Vulkan, but there isn't much of anything to show with regard to that yet.

I made this standalone version very quickly over the course of just 2 days, but that's because I copied off of my own homework, with the result being something that has aspects from the original kmixer (formerly kaudio), the new kmixer, and kmixerAsync (which can be considered a separate thing).

Anyway, here's the code that makes it all work, being just shy of 1000 lines: