Merge branch 'master' into jgrpp-nrt

Merge NRT feature

# Conflicts:
#	docs/landscape.html
#	docs/landscape_grid.html
#	src/bridge_map.h
#	src/build_vehicle_gui.cpp
#	src/company_base.h
#	src/company_cmd.cpp
#	src/misc_gui.cpp
#	src/newgrf.cpp
#	src/newgrf_engine.cpp
#	src/pathfinder/follow_track.hpp
#	src/pathfinder/npf/npf.cpp
#	src/road_cmd.cpp
#	src/road_func.h
#	src/road_gui.cpp
#	src/road_map.h
#	src/road_type.h
#	src/roadveh_cmd.cpp
#	src/saveload/afterload.cpp
#	src/saveload/company_sl.cpp
#	src/script/api/script_bridge.cpp
#	src/table/newgrf_debug_data.h
#	src/tile_cmd.h
#	src/town_cmd.cpp
#	src/tunnel_map.h
#	src/tunnelbridge_cmd.cpp

src/ground_vehicle.hpp

@@ -37,7 +37,7 @@ struct GroundVehicleCache {
 	uint16 cached_axle_resistance;  ///< Resistance caused by the axles of the vehicle (valid only for the first engine).
 
 	/* Cached acceleration values, recalculated on load and each time a vehicle is added to/removed from the consist. */
-	uint16 cached_max_track_speed;  ///< Maximum consist speed limited by track type (valid only for the first engine).
+	uint16 cached_max_track_speed;  ///< Maximum consist speed (in internal units) limited by track type (valid only for the first engine).
 	uint32 cached_power;            ///< Total power of the consist (valid only for the first engine).
 	uint32 cached_air_drag;         ///< Air drag coefficient of the vehicle (valid only for the first engine).