Added lighting engine module

- New lighting engine module which contains new data types Light and
Material. These data types and functions facilitates making a basic 3D
iluminated program with a light and a model.

- Added lighting engine module example (currently included in raylib.h;
it might be compiled by separate and include lighting.h in game source C
file).

- Corrected some opengl defines control structures and added some TODO
to fix raylib-opengl 1.1 source build (note: now source can be compiled
without errors, but rlglReadPixels() won't work properly).

Note: most of functions of phong version 330 shader are not in v100
shaders, so I couldn't write a version 100 phong shader. These functions
are included from version 150.

src/lighting.c

@@ -0,0 +1,124 @@
+/**********************************************************************************************
+*
+*   raylib lighting engine module - Lighting and materials management functions
+*
+*   Copyright (c) 2015 Victor Fisac and Ramon Santamaria
+*
+*   This software is provided "as-is", without any express or implied warranty. In no event
+*   will the authors be held liable for any damages arising from the use of this software.
+*
+*   Permission is granted to anyone to use this software for any purpose, including commercial
+*   applications, and to alter it and redistribute it freely, subject to the following restrictions:
+*
+*     1. The origin of this software must not be misrepresented; you must not claim that you
+*     wrote the original software. If you use this software in a product, an acknowledgment
+*     in the product documentation would be appreciated but is not required.
+*
+*     2. Altered source versions must be plainly marked as such, and must not be misrepresented
+*     as being the original software.
+*
+*     3. This notice may not be removed or altered from any source distribution.
+*
+**********************************************************************************************/
+
+//#define LIGHTING_STANDALONE     // NOTE: To use the lighting module as standalone lib, just uncomment this line
+
+#if defined(LIGHTING_STANDALONE)
+    #include "lighting.h"
+#else
+    #include "raylib.h"
+#endif  
+             
+#include <string.h>
+
+//----------------------------------------------------------------------------------
+// Defines and Macros
+//----------------------------------------------------------------------------------
+//...
+
+//----------------------------------------------------------------------------------
+// Types and Structures Definitions
+//----------------------------------------------------------------------------------
+//...
+
+//----------------------------------------------------------------------------------
+// Module Functions Definition
+//----------------------------------------------------------------------------------
+
+// Lights functions
+void SetLightPosition(Light *light, Vector3 position)
+{
+    light->position[0] = position.x;
+    light->position[1] = position.y;
+    light->position[2] = position.z;
+}
+
+void SetLightRotation(Light *light, Vector3 rotation)
+{
+    light->rotation[0] = rotation.x;
+    light->rotation[1] = rotation.y;
+    light->rotation[2] = rotation.z;
+}
+
+void SetLightIntensity(Light *light, float intensity)
+{
+    light->intensity[0] = intensity;
+}
+
+void SetLightAmbientColor(Light *light, Vector3 color)
+{
+    light->ambientColor[0] = color.x;
+    light->ambientColor[1] = color.y;
+    light->ambientColor[2] = color.z;
+}
+
+void SetLightDiffuseColor(Light *light, Vector3 color)
+{
+    light->diffuseColor[0] = color.x;
+    light->diffuseColor[1] = color.y;
+    light->diffuseColor[2] = color.z;
+}
+
+void SetLightSpecularColor(Light *light, Vector3 color)
+{
+    light->specularColor[0] = color.x;
+    light->specularColor[1] = color.y;
+    light->specularColor[2] = color.z;
+}
+
+void SetLightSpecIntensity(Light *light, float specIntensity)
+{
+    light->specularIntensity[0] = specIntensity;
+}
+
+// Materials functions
+void SetMaterialAmbientColor(Material *material, Vector3 color)
+{
+    material->ambientColor[0] = color.x;
+    material->ambientColor[1] = color.y;
+    material->ambientColor[2] = color.z;
+}
+
+void SetMaterialDiffuseColor(Material *material, Vector3 color)
+{
+    material->diffuseColor[0] = color.x;
+    material->diffuseColor[1] = color.y;
+    material->diffuseColor[2] = color.z;    
+}
+
+void SetMaterialSpecularColor(Material *material, Vector3 color)
+{
+    material->specularColor[0] = color.x;
+    material->specularColor[1] = color.y;
+    material->specularColor[2] = color.z;
+}
+
+void SetMaterialGlossiness(Material *material, float glossiness)
+{
+    material->glossiness[0] = glossiness;
+}
+
+void SetMaterialNormalDepth(Material *material, float depth)
+{
+    material->normalDepth[0] = depth;
+}