Replaced by example rlgl_oculus_rift

The first target allow makefile to install the dev files (static library and
header) to standard directories on GNU/Linux platforms; the second allow it to
unistall (remove) the dev files.

It needs lot of improvements.

Set makefile to default OpenGL 3.3 compilation

Develop branch integration

Some review work still required...

Corrected lighting system crash and VR variables not found...

Matching the same stereo rendering result given by Oculus PC SDK for
Oculus Rift CV1 is very difficult because hardware has changed a lot and
DK2 distortion shader and parameters don't fit on CV1. Some custom
parameters have been calculated to simulate kind of CV1 stereo
rendering. Further work is required on this point.

Simulator configuration is directly obtained from VR device parameters!

Oculus Rift CV1 default values seem not to be available...

...at least, directly, available if using directly audio module...

- Embedded VR distortion shader
- Ready to support multiple VR devices
- Fallback to VR Simulator if device not ready
- Support mono rendering over stereo rendering

-IN PROGRESS-

...to avoid dynamic conditions on for loop (lightsCount) on standard
shader, it seems GLSL 100 doesn't support that feature... on some GPUs
like RaspberryPi...

Stereo rendering has been moved again to Begin3dMode() and End3dMode(),
it has some limitations but makes more sense...

Still thinking about the best way to manage this...