Stop keeping unused token once user successfully logs in.
Fix missing update of token update date.
Counters wouldn't get updated for stage=LOGOUT
wifidog/auth/index.php: Added a Messages: response in addition to Auth: so we can know what the hell the server is up to. Currently you need to run wifidog in debug level 7 to see it. That message should be parsed so it is visible in debug level 6.