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/livery.h

@@ -61,7 +61,7 @@ DECLARE_POSTFIX_INCREMENT(LiveryScheme)
 template <> struct EnumPropsT<LiveryScheme> : MakeEnumPropsT<LiveryScheme, byte, LS_BEGIN, LS_END, LS_END, 8> {};
 
 /** List of different livery classes, used only by the livery GUI. */
-enum LiveryClass {
+enum LiveryClass : byte {
 	LC_OTHER,
 	LC_RAIL,
 	LC_ROAD,
@@ -73,6 +73,7 @@ enum LiveryClass {
 	LC_GROUP_AIRCRAFT,
 	LC_END
 };
+DECLARE_ENUM_AS_ADDABLE(LiveryClass)
 
 /** Information about a particular livery. */
 struct Livery {