Fixed bug relating to alt key

main.go

@@ -31,6 +31,7 @@ func main () {
 	application.OnStart(onStart)
 	application.OnResize(redraw)
 	application.OnPress(onPress)
+	application.OnRelease(onRelease)
 	
 	err = application.Run()
 	if err != nil { panic(err) }
@@ -217,6 +218,7 @@ func onRelease (button stone.Button) {
 	switch button {
 	case stone.KeyLeftAlt, stone.KeyRightAlt:
 		inputState.alt = false
+		println("alt up")
 	}
 }