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/Box3f.h

@@ -0,0 +1,37 @@
+#ifndef BH_MATH_BOX3F_H
+#define BH_MATH_BOX3F_H
+
+#include "../Common.h"
+
+
+void BH_Box3fUnion(const float aMin[3],
+                   const float aMax[3],
+                   const float bMin[3],
+                   const float bMax[3],
+                   float outMin[3],
+                   float outMax[3]);
+
+
+
+int BH_Box3fIntersect(const float aMin[3],
+                      const float aMax[3],
+                      const float bMin[3],
+                      const float bMax[3],
+                      float outMin[3],
+                      float outMax[3]);
+
+
+
+int BH_Box3fContains(const float aMin[3],
+                     const float aMax[3],
+                     const float point[3]);
+
+
+
+int BH_Box3fEnclose(const float *points,
+                    size_t size,
+                    float outMin[3],
+                    float outMax[3]);
+
+
+#endif /* BH_MATH_BOX3F_H */