* Add panning to raudio and update audio_raw_stream example.

* remove pan smoothing, code formatting changes following pull request comments

Co-authored-by: Ray <raysan5@gmail.com>

Allow to choose which modules are compiled with raylib, if some modules are excluded from compilation, required functionality is not available but smaller builds are possible.

- All variables are initialized on declaration, some arrays were not properly initialized
 - Static array buffers require memset() for re-initialization on every function call

Following english rules, it should be singular name before Count.

This is a big change for optimization and a more professional understanding of audio. Instead of dealing with samples, now we deal with frames, like miniaudio does, so, avoiding continuous conversions from samples to frames.

rlgl has been redesigned to avoid any dependency to `raylib` or `raymath`, all functions using some of those libs have been reviewed.
 - REMOVED: `Texture2D`, `Shader` structs dependency
 - REMOVED: `Vector3`, `Matrix` structs dependency
 - REMOVED: raymath functions dependency, all required math is implemented in rlgl
 - ADDED: `rlMatrix` custom rlgl type
 - ADDED: `utils.c`: `rlMatrixFromMatrix()` and `rlMatrixToMatrix()` for a safe conversion between raylib<->rlgl matrix types
 - ADDED: `rl` prefix to all `rlgl` structs
 - Other small tweaks here and there

RENAMED: InitAudioStream() -> LoadAudioStream()
RENAMED: CloseAudioStream() -> UnloadAudioStream()