TIC-TAC-TOE (Naelys)

The game has been done within Jean-Philippe Pareins course "Maîtriser Unity et le C# | Guide Complet Développeur" https://www.udemy.com/course/maitriser-unity-2018-et-le-c-formation-complete/ (course in french) I made an additionnal menu and a two players mode. The code has been slightly changed.