GLSL 'include' support

res/shaders/lib/commons.glsl

@@ -0,0 +1,11 @@
+// Example of a GLSL library
+
+vec4 decompress_light(float compressed_light) {
+	vec4 result;
+    int compressed = floatBitsToInt(compressed_light);
+    result.r = ((compressed >> 24) & 0xFF) / 255.f;
+    result.g = ((compressed >> 16) & 0xFF) / 255.f;
+    result.b = ((compressed >> 8) & 0xFF) / 255.f;
+    result.a = (compressed & 0xFF) / 255.f;
+	return result;
+}