Merge branch 'extra_large_maps-sx' into jgrpp

Conflicts:
	src/saveload/extended_ver_sl.cpp
	src/saveload/extended_ver_sl.h

src/saveload/extended_ver_sl.h

@@ -44,6 +44,7 @@ enum SlXvFeatureIndex {
 	XSLFI_TRAFFIC_LIGHTS,                         ///< This save game uses road traffic lights
 	XSLFI_RAIL_AGEING,                            ///< This save game uses the rail aging patch
 	XSLFI_SPRINGPP,                               ///< This is a SpringPP game, use this for loading some settings
+	XSLFI_EXTRA_LARGE_MAP,                        ///< Extra large map
 
 	XSLFI_SIZE,                                   ///< Total count of features, including null feature
 };