Remove dr_wav.h

[ggerganov]

In order to be as minimalistic as possible, it would be nice to avoid having dr_wav.h in the project. We use it for a very small subset of functionality - to read 16-bit PCM audio. It should be easy to implement it from scratch.

[kurbus]

In C, you can always get more compact. If you wanted, you could only have just 1 C file that has 400 lines before int main(). and also, doesn't it always compile to the same binary? (Please don't quote me on this)