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

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

Now it's easier for the user! Just init Oculus device and get stereo
rendering!

Tint color could be applied to colDiffuse... but what's the best way?
Replace it? Multiply by? A point to think about...

texture2D() is deprecated on GLSL 330

NOTE: It requires a depth texture as input, it should be configured on
rlgl, by default RenderTexture (fbo) uses Depth Renderbuffer instead of
Depth Texture. Check rlglLoadRenderTexture()