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/Box2f.h

@@ -0,0 +1,37 @@
+#ifndef BH_MATH_BOX2F_H
+#define BH_MATH_BOX2F_H
+
+#include "../Common.h"
+
+
+void BH_Box2fUnion(const float aMin[2],
+                   const float aMax[2],
+                   const float bMin[2],
+                   const float bMax[2],
+                   float outMin[2],
+                   float outMax[2]);
+
+
+
+int BH_Box2fIntersect(const float aMin[2],
+                      const float aMax[2],
+                      const float bMin[2],
+                      const float bMax[2],
+                      float outMin[2],
+                      float outMax[2]);
+
+
+
+int BH_Box2fContains(const float aMin[2],
+                     const float aMax[2],
+                     const float point[2]);
+
+
+
+int BH_Box2fEnclose(const float *points,
+                    size_t size,
+                    float outMin[2],
+                    float outMax[2]);
+
+
+#endif /* BH_MATH_BOX2F_H */