Merge branch 'save_ext' into jgrpp

# Conflicts:
#	config.lib
#	src/misc_gui.cpp
#	src/network/network_gui.cpp
#	src/settings_type.h
#	src/smallmap_gui.cpp
#	src/smallmap_gui.h
#	src/station_cmd.cpp
#	src/toolbar_gui.cpp
#	src/vehicle_gui.cpp
#	src/window.cpp

src/window_gui.h

@@ -726,13 +726,18 @@ public:
 	/**
 	 * Called once per (game) tick.
 	 */
-	virtual void OnTick() {}
+	virtual void OnGameTick() {}
 
 	/**
 	 * Called once every 100 (game) ticks.
 	 */
 	virtual void OnHundredthTick() {}
 
+	/**
+	 * Called periodically.
+	 */
+	virtual void OnRealtimeTick(uint delta_ms) {}
+
 	/**
 	 * Called when this window's timeout has been reached.
 	 */