* Update to miniaudio 0.10
This replaces the old ma_pcm_converter with ma_data_converter.
At this time of this commit, miniaudio 0.10 is still in the testing
phase. To make it easier to update miniaudio.h during this period, I've
temporarily moved the @raysan5 Win32 customizations to raudio.c because
there may be quite a few updates to miniaudio.h during this time.
* Use miniaudio's built-in volume control.
Found some issues when building for web using latest emscripten 1.38.30, traced the error and found that eglGetProcAdress does not return function pointers for VAO functionality, supported by extension.
It requires more investigation but now it works (avoiding VAO usage)
