Swith orx-glslify to preprocessor usage

orx-glslify/src/test/resources/glslify/glsl-luma/index.glsl

@@ -0,0 +1,9 @@
+float luma(vec3 color) {
+  return dot(color, vec3(0.299, 0.587, 0.114));
+}
+
+float luma(vec4 color) {
+  return dot(color.rgb, vec3(0.299, 0.587, 0.114));
+}
+
+#pragma glslify: export(luma)