Cleanup: remove clone function from basic vec operations

- commented all functions in mat4.h
- add shared math header

src/math/common_math.h

@@ -0,0 +1,20 @@
+// Common math library
+
+#ifndef MATH_H
+#define MATH_H
+
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#if defined(__x86_64__) || defined(__i386__)
+    #define SIMD_X86
+    #include <xmmintrin.h>
+#elif defined(__aarch64__) || defined(__arm64__)
+    #define SIMD_ARCH
+    #include <arm_neon.h>
+#else
+    #define SIMD_NONE
+#endif
+
+#endif // MATH_H