updated makefile for supporting different target architectures

use "ARCH=arch_name make"

restructured project folder, implementations and headers together under sources/

sources/GL_STUFF/UTILS/OnlyOnce.hpp

@@ -0,0 +1,5 @@
+#pragma once
+
+#include <GLES2/gl2.h>
+
+GLuint loadImg(const char* path);