Already integrated into raylib

- No default VR device parameteres inside raylib
- VR device parameter should be provided by user
- VR distortion shader should be provided by user

Happy new year 2019

Some tweaks

Issue was related to vertex tangent attibutes not uploaded to GPU, a quick solution was implemented for new vertex attributes loading for already existing meshes... I don't like it specially but it will work for now.

Multiple functions added and some reviewed to adapt to the new multi-mesh, multi-material and animated models.

Removed trail spaces

Added `DrawRoundedRect()` and `DrawRoundedRectLines()`

- Support compiling for OpenGL 1.1
- Free meshes/materials memory after usage...

One mesh files can be loaded correctly

MISSING:
 - Multimesh OBJ loading
 - Materials loading

It seems obj loading is working ok but there is some problem with drawing...

Added DrawRing(), DrawRingLines() and DrawCircleSectorLines()