Add love.joystick.reload, remove love.joystick.open and friends. (issue #392)

Reload originates from love-experiments, as noted in the ticket.

src/modules/joystick/sdl/Joystick.h

@@ -45,6 +45,7 @@ namespace sdl
 		// Implements Module.
 		const char * getName() const;
 
+		void reload();
 		bool checkIndex(int index);
 		int getNumJoysticks();
 		const char * getName(int index);