Merge branch 'master' into jgrpp

Bump savegame for water regions for ship pathfinder
Use ring_buffer for ShipPathCache

src/track_type.h

@@ -91,6 +91,8 @@ enum Trackdir : byte {
 	INVALID_TRACKDIR  = 0xFF,       ///< Flag for an invalid trackdir
 };
 
+/** Allow incrementing of Trackdir variables */
+DECLARE_POSTFIX_INCREMENT(Trackdir)
 /** Define basic enum properties */
 template <> struct EnumPropsT<Trackdir> : MakeEnumPropsT<Trackdir, byte, TRACKDIR_BEGIN, TRACKDIR_END, INVALID_TRACKDIR, 4> {};