Clear cache countdown

Make the number 20 in this message count down as seconds pass. Would be useful for people with bad timing. I often click it too soon which then resets the timer.

Tbh I'm not sure why this error is necessary. Can't the server just instantly terminate any existing sessions when new logins happen? @Teifion

This is in place because one client would disconnect the other which would then try to reconnect. It was the only way i found to reliably stop login flood spam.

The login mechanism references in this issue no longer exists, obsolete.