Merge branch 'master' into jgrpp

# Conflicts:
#	.gitignore
#	CMakeLists.txt
#	src/3rdparty/optional/optional.hpp
#	src/group_cmd.cpp
#	src/industry_cmd.cpp
#	src/misc_gui.cpp
#	src/video/sdl2_v.cpp

src/string_type.h

@@ -15,10 +15,10 @@
 #include <string>
 
 /** A non-breaking space. */
-#define NBSP "\xC2\xA0"
+#define NBSP u8"\u00a0"
 
 /** A left-to-right marker, marks the next character as left-to-right. */
-#define LRM "\xE2\x80\x8E"
+#define LRM u8"\u200e"
 
 /**
  * Valid filter types for IsValidChar.