11. Change the networking code, so that a single server can connect two clients with each other. The server should provide player 1 with a code, and player 2 can connect with player 1 using that code (essentially like a room).
12. Add a --help option, that displays information about the game and how to run it.
13. Add better error-checking to check_server() and check_client() (Use check_server_client() as inspiration).
14. Ensure that check_server() and check_client() work properly for command-line invocation, then remove check_server_client().