* don't check authentication if the network doesn't need to
register
* don't pass through muser for ZNC type messages
* avoid duplicate message for queries containing highlights
* make a copy of the cast for metadata analysis to avoid poisoning it
* set up callback for when the instance is authenticated, so we can
request a LIST immediately if so desired
* separate out seeding functions to populate CHANLIMIT to ease future
work involving other options, such as PREFIX