bugfix: error message on untested version

We needed to initialize App.screen dimensions in this fork.

pong.lua

@@ -8,7 +8,8 @@ end
 function pong.initialize(arg)
 	love.graphics.setBackgroundColor(1,1,1)
 	log_new('session')
-	love.window.setMode(N*3, N*3)  -- the court
+	App.screen.width, App.screen.height = N*3, N*3  -- the court
+	App.screen.resize(App.screen.width, App.screen.height)
 	if Settings and Settings.pong then
 		pong.load_settings()
 	else