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/Line.h

@@ -0,0 +1,23 @@
+#ifndef BH_MATH_LINE_H
+#define BH_MATH_LINE_H
+
+#include "../Common.h"
+
+
+int BH_LineFromPoints(const float a[2],
+                      const float b[2],
+                      float out[3]);
+
+
+
+float BH_LineDistance(const float line[3],
+                      const float point[2]);
+
+
+
+void BH_LineClosestPoint(const float line[3],
+                         const float point[2],
+                         float out[2]);
+
+
+#endif /* BH_MATH_LINE_H */