Refactor, separate docs from headers, add ru docs

Doxygen kind'a sucks and I need multilanguage documentation, so I did
that. Also, separated massive Math.h file into smaller files.

include/BH/Math/Vec4i.h

@@ -0,0 +1,54 @@
+#ifndef BH_MATH_VEC4I_H
+#define BH_MATH_VEC4I_H
+
+#include "../Common.h"
+
+
+void BH_Vec4iAdd(const int a[4],
+                 const int b[4],
+                 int out[4]);
+
+
+
+void BH_Vec4iSub(const int a[4],
+                 const int b[4],
+                 int out[4]);
+
+
+
+void BH_Vec4iMul(const int a[4],
+                 const int b[4],
+                 int out[4]);
+
+
+
+void BH_Vec4iScale(const int a[4],
+                   int b,
+                   int out[4]);
+
+
+
+void BH_Vec4iMulAdd(const int a[4],
+                    const int b[4],
+                    const int c[4],
+                    int out[4]);
+
+
+
+void BH_Vec4iNegate(const int in[4],
+                    int out[4]);
+
+
+
+void BH_Vec4iMin(const int a[4],
+                 const int b[4],
+                 int out[4]);
+
+
+
+void BH_Vec4iMax(const int a[4],
+                 const int b[4],
+                 int out[4]);
+
+
+#endif /* BH_MATH_VEC4I */