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

cmake/CompileFlags.cmake

@@ -16,6 +16,13 @@ macro(compile_flags)
         endif()
     endif()
 
+    # Our strings are UTF-8.
+    if(MSVC)
+        add_compile_options(/utf-8)
+    else()
+        add_compile_options(-finput-charset=utf-8)
+    endif()
+
     # Add some -D flags for Debug builds. We cannot use add_definitions(), because
     # it does not appear to support the $<> tags.
     add_compile_options(