Don't allow users to join channels they are already in
Fix Stas::Unserialize to return the instance
Close timed out proxyscan sockets better
Add "virtual mode" support

This allows fully tracking extbans and other modes set by a different
underlying mode, such as InspIRCd's namedmodes

Add two configuration options to cs_ban to configure which mode is set
and whether or not to kick banned users.

Add default "mute" fantasy command to botserv.example.conf