Services fixes

This PR makes the following fixes:
- Fix the first user on a channel still have chanop status by removing all default statuses for registered channels (fixes #68)
- Make sure a user's status is high enough to set an autostatus extban and remove their statuses upon logout (fixes #75)
- Fix ChanServ not restoring modes upon channel recreation (fixes #81)
- Lowercase all NickServ nicknames so they can be matched case insensitively (fixes #82)