Changing examples to use makefile

- Testing a modified version of the makefile from raylib Instead of multiple project files for examples.
- Fixed readme example

Examples/Examples/models/resources/shaders/cubemap.fs

@@ -1,38 +0,0 @@
-/*******************************************************************************************
-*
-*   rPBR [shader] - Equirectangular to cubemap fragment shader
-*
-*   Copyright (c) 2017 Victor Fisac
-*
-**********************************************************************************************/
-
-#version 330
-
-// Input vertex attributes (from vertex shader)
-in vec3 fragPos;
-
-// Input uniform values
-uniform sampler2D equirectangularMap;
-
-// Output fragment color
-out vec4 finalColor;
-
-vec2 SampleSphericalMap(vec3 v)
-{
-    vec2 uv = vec2(atan(v.z, v.x), asin(v.y));
-    uv *= vec2(0.1591, 0.3183);
-    uv += 0.5;
-    return uv;
-}
-
-void main()
-{
-    // Normalize local position 
-    vec2 uv = SampleSphericalMap(normalize(fragPos));
-
-    // Fetch color from texture map
-    vec3 color = texture(equirectangularMap, uv).rgb;
-
-    // Calculate final fragment color
-    finalColor = vec4(color, 1.0);
-}