(svn r6513) -Codechange: unified the code to draw depot windows

This change is intended to make it easier to make depot behaviour consistent
   and faster to code when adding more features in the future
   The user interface should hopefully not be affected by this

depot.h

@@ -56,6 +56,8 @@ static inline void DeleteDepot(Depot *depot)
 	depot->xy = 0;
 }
 
+void ShowDepotWindow(TileIndex tile, byte type);
+
 #define FOR_ALL_DEPOTS_FROM(d, start) for (d = GetDepot(start); d != NULL; d = (d->index + 1 < GetDepotPoolSize()) ? GetDepot(d->index + 1) : NULL) if (IsValidDepot(d))
 #define FOR_ALL_DEPOTS(d) FOR_ALL_DEPOTS_FROM(d, 0)