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/town_type.h

@@ -28,6 +28,7 @@ enum TownSize {
 	TSZ_END,    ///< Number of available town sizes.
 };
 template <> struct EnumPropsT<TownSize> : MakeEnumPropsT<TownSize, byte, TSZ_SMALL, TSZ_END, TSZ_END, 2> {};
+DECLARE_ENUM_AS_ADDABLE(TownSize)
 
 enum Ratings {
 	/* These refer to the maximums, so Appalling is -1000 to -400
@@ -92,6 +93,7 @@ enum TownLayout : byte {
 	NUM_TLS,             ///< Number of town layouts
 };
 template <> struct EnumPropsT<TownLayout> : MakeEnumPropsT<TownLayout, byte, TL_BEGIN, NUM_TLS, NUM_TLS, 3> {};
+DECLARE_ENUM_AS_ADDABLE(TownLayout)
 
 /** Town founding setting values. It needs to be 8bits, because we save and load it as such */
 enum TownFounding : byte {