replace math_graphics with glm version 1.0.3

libs/glm/test/gtx/gtx_texture.cpp

@@ -0,0 +1,23 @@
+#include <glm/vec2.hpp>
+
+#define GLM_ENABLE_EXPERIMENTAL
+#include <glm/gtx/texture.hpp>
+
+static int test_levels()
+{
+	int Error = 0;
+
+	int const Levels = glm::levels(glm::ivec2(3, 2));
+	Error += Levels == 2 ? 0 : 1;
+
+	return Error;
+}
+
+int main()
+{
+	int Error = 0;
+
+	Error += test_levels();
+
+	return Error;
+}