* 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.

* Fix olds directories used and windows/linux portability

* Fix windows/linux portability

Co-authored-by: Simon <simon@frithrah.com>

Removed functions from rlgl module.

Simplified some parts and reviewed for a correct computation of matrices, considering stereo render view/projection per eye transformations

shaders_rlgl_mesh_instanced -> shaders_mesh_instancing

* adds DrawTexturedPoly with example

* the actual example ... ahem

* moved DrawTexturePoly to textures function and example
NB function name changed to fit with other DrawTextureXXX functions
(no "d" )

Co-authored-by: codifies <you@example.com>

* Fix some warnings in examples.

* cleanups from review

Co-authored-by: Jeffery Myers <JefMyers@blizzard.com>

- Some rlgl functions have been moved to core
 - Some functions have been made internal to rlgl
 - rlgl functions prefixed with rl*()

Vr simulator has been moved to core module and completely redesigned. Now user is in charge of stereo-render fbo and also in full control of distortion shader. Code is a bit more complex but better aligned with other raylib examples.

Co-authored-by: Simon <simon@frithrah.com>