Move to own header for a more deep review of the module

Added experimental network module

At least until a proper solution is found!

Removed a useless semicolon.

This needs to be tested on a hi-DPI monitor, probably requiring a FLAG to enable it would be a good idea...

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

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

- 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...