In particular, allow hostnames without periods (like on a LAN).
This shouldn't be a client compability concern since we allow
vhosts without periods.

* Fix #684
* Fix #683
* Add `CHANSERV CLEAR`
* Allow mode changes from channel founders even when they aren't joined
* Operators with the chanreg capability are exempt from max-channels-per-account
* Small fixes and cleanup

* Fix #679 (borked reply to `JOIN #chan,\r\n`)
* Replace invalid error parameters with *'s in various places
* Fix PART with no message sending an empty trailing parameter to the channel
* Fix some error responses not getting labeled

Includes a partially backwards-incompatible config change

Workaround for #661: this makes the `CAP LS 302` line from the default config
fit on a single line, as long as the server name is at most 35 characters.

tor-listeners.listeners was checked against listen,
but listen is obsolete now, so config load would fail
on a config that used the new style `listeners` instead of
`listen` --- unless tor-listeners.listeners was empty, which
it should be under the new style, but there's no need to enforce
that