modify player_auth to allow multiple logins per player (limit to 3 for now)

* Fixes #98 (we'd talked about doing other things for this, but, in fact, if letting people stay logged in from multiple computers works, i think that is sufficient for that ticket.  If it doesn't work, i'm sure people will let me know.)
* Jenkins: http://jenkins.buttonweavers.com:8080/job/buttonmen-cgolubi1/186/
* requires a database update to modify the player_auth table