expiration for always-on clients

Fixes #810

New Crowdin updates

Enhancements to CS PURGE

New Crowdin updates

1. Consolidate PURGE and UNPURGE into subcommands
2. Add PURGE LIST
3. PURGE ADD now requires a confirmation code

Fixes #1294

fix critical bugs in RENAME

fix #1449

fix #1452

Channel rename (both of registered and unregistered channels) would leave
the old name unreclaimable.

fix #1260

Fixes #1260

New Crowdin updates

New Crowdin updates

INVITE playback (#1409) was buggy, due to the double use of (Item).Params[0]
for the channel name and the recipient nick. Stuff the channel name in
(Item).Message.Message instead.

DEFCON 4 and lower should require SASL from Tor users

make CAP LS/LIST respect the MaxLineLen constant

New Crowdin updates

add a mysql quickstart guide

clean up some config comments

manual updates for nick reservation and email verification

introduce "flat ip" representations

This didn't work correctly for IPv6 or custom nets.
/UNDLINE IP can temporarily be used to reset the throttle.

fix #1439, give all atheme group founders +q

Validate imported databases for confusable nicks

{default,traditional}.yaml: refer to IPs/CIDR instead of addrs

Whenever CIDR is mentioned in the config, it's in combination with IP so
talking about addressese in these points gives wrong impression that a
domain name would be valid as those are often thought as addresses.