Merge branch 'master' into jgrpp

# Conflicts:
#	src/airport_gui.cpp
#	src/build_vehicle_gui.cpp
#	src/direction_type.h
#	src/gfx_type.h
#	src/group_gui.cpp
#	src/misc_gui.cpp
#	src/rail_gui.cpp
#	src/road_gui.cpp
#	src/signs_gui.cpp
#	src/slope_func.h
#	src/smallmap_gui.cpp
#	src/terraform_gui.cpp
#	src/toolbar_gui.cpp
#	src/town_gui.cpp
#	src/town_type.h
#	src/vehicle_type.h
#	src/widget_type.h

src/vehicle_type.h

@@ -37,6 +37,7 @@ enum VehicleType : byte {
 DECLARE_POSTFIX_INCREMENT(VehicleType)
 /** Helper information for extract tool. */
 template <> struct EnumPropsT<VehicleType> : MakeEnumPropsT<VehicleType, byte, VEH_TRAIN, VEH_END, VEH_INVALID, 3> {};
+DECLARE_ENUM_AS_ADDABLE(VehicleType)
 
 struct Vehicle;
 struct Train;