sse2 version of vec4 dot product

* use this for normalizing vector

test/src/test_main.c

@@ -26,7 +26,10 @@ main(int argc, const char * argv[]) {
     cmocka_unit_test(test_euler),
 
     /* quaternion */
-    cmocka_unit_test(test_quat)
+    cmocka_unit_test(test_quat),
+
+    /* vec4 */
+    cmocka_unit_test(test_vec4)
   };
 
   return cmocka_run_group_tests(tests, NULL, NULL);