By default, we look for texture1 for LOC_MAP_SPECULAR and texture2 for
LOC_MAP_NORMAL

Added  clean to Makefile for FreeBSD

Full sources already included and compiled with raylib (rglfw)

Only required by examples

Just in case of legal conflict with public domain software, added MIT
alternative license.

This commit should bring the mini_al backend up to feature parity with
the OpenAL backend.

...to define proper values

Compiling GLFW library with raylib avoids external dependencies, this
way we solve version problems in some platforms

Now header is truly multiplatform...

Actually still a small pending check on XBOX gamepad controls that
hopefully will be removed with next GLFW 3.3

Support Universal Windows Platform (UWP):
- Windows 10 App
- Windows Phone
- Xbox One

Store the default shaders

libEGL and libGLESv2 have been renamed on latest Raspbian Stretch
version (also included on latest Jessie upgrade).

It seems to be done to avoid conflicts between official Mesa libs and
Broadcomm provided ones.

USE_DEPTH_RENDERBUFFER on OpenGL 2.1

Not tested, could have errors

On RPI, after latest drivers update, models were not rendered properly
cause of that...

Have SetShaderValue(i) take a const pointer

Could correct possible issues on OpenGL 1.1