Improved joystick management.

With this update, I have improved the behavior of the game when the joystick is moved diagonally.

This should help the gameplay, so I suggest to get rid of the files ( snakez_j.tap  and snakez_j.wav) if downloaded before 24 january 2025  and get the last versions!

Note: the keyboard gameplay has not changed, so if you don't have a joystick you can skip this update.