Added optional callback function when transition is done

example/game.gui_script

@@ -14,7 +14,9 @@ end
 function on_input(self, action_id, action)
 	if action_id == hash("touch") and action.released then
 		if gui.pick_node(gui.get_node("win_button"), action.x, action.y) then
-			monarch.show(hash("menu"), true)
+			monarch.show(hash("menu"), { clear = true }, function()
+				print("showing menu done")
+			end)
 		end
 	end
 end