AWAY status should be tracked per-session:
1. With auto-away enabled, away status is aggregated across sessions
(if any session is not away, the client is not away, else use
the away status that was set most recently)
2. With auto-away disabled, we get the legacy behavior where AWAY
applies directly to the client
implement candidate compromise proposal for websockets
1. Text and binary frames are accepted
2. Text frames are sent by default
3. Binary frames are sent to clients who negotiate `binary.ircv3.net`
4. Non-UTF8 data is not accepted (enabling websockets still enables UTFONLY)
checkAlwaysOnExpirationNoMutex was respecting registered status, but
always-on clients were not considered registered at the time of the
initial check, so they were being created regardless of expiration.
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.
Tor listeners should never see an STS cap.
Add an undocumented 'hide-sts' key for listeners that hides the STS cap.
This can be used if the listener is secured at layer 3 or 4 (VPNs,
E2E mixnets). It will be necessary to add the relevant IPs to `secure-nets`.
Store the channel-user modes of always-on clients along with their
channel memberships, restore them on server startup. This will coexist
alongside /CS AMODE, which autoapplies modes to clients on join regardless
of their always-on status.
CLIENTS LIST shows information about clients attached to a nick.
CLIENTS LOGOUT allows individual (or all) sessions to be logged out.
SESSIONS is now an alias for CLIENTS LIST.
Fixes #1072.