Bad usernames could crash the server

[pegelf]

During a test round, some very long usernames caused the server to crash. I don't know if it's just the length or also special characters.

[CitrusToffee]

With basically every combination I couldn't get any crashes. Even a combination of ' " ` didn't crash anything.

Also the input tells me to limit the number of letters to 13.-ish for the name.