Moved to raudio library repo: https://github.com/raysan5/raudio

Note this new raygui version embeds ricons and `GuiTextBoxMulti()` is not working properly

* Added an example for raylib OpenGL interop.

* Removed C99 variable-length array to fix MSVC errors

* Moved the opengl interop example from shaders to others.

It's broken.

- Removed raylib_demo (outdated)
- Removed some old examples