fix #1076

fix #1058

fix #1080

Apply default user modes just before registration.

Fix issue with one-character args in ArgsToStrings.

New Crowdin translations

Previously, we were applying defaults before the user had completed
registration. This meant that the number of invisible users was
incremented when the user connected, and then the total was incremented
when registration was completed.

Now both counters are updated at the same time. If a user disconnects
prior to registration, +i has not yet been applied so it would not be
decremented.

fix #1061

fix #1057

Ignore non-privmsg commands to services.

This avoids "No such nick" responses to +draft/typing TAGMSG, etc.

add changelog for v2.1.0-rc1

change the default self-signed certificate filenames

fix TAGMSG playback

1. TAGMSG were incorrectly being considered multilines, because
   Is512() was checking the wrong thing
2. Playback of TAGMSG should depend on event-playback, not on message-tags

/ns erase should confirm with /ns erase rather than unregister.

tweak version strings again

clean up account-notify logout notification