mod_smacks: Bounce unacked stanzas on shutdown

mod_smacks: Preserve counter values on shutdown

mod_smacks: Simplify access to local user sessions Less to type if per chance the next commit also wants to access sessions.

mod_smacks: Cancel hibernation when session is closed To ensure that if a session is replaced after it has gone into hibernation, it does not come back and cause trouble for the new session (see previous commit).

mod_smacks: Skip hibernation logic if session was closed or replaced The resumption_token is removed when the session is closed via the pre-session-close event, signaling that it cannot be resumed, and therefore no hibernation timeout logic should be invoked. Fixes that if a session somehow is replaced by a new one using the same resource (which is the common behavior), the old session would still be around until it times out at which point it sends `<presence type="unavailable"/>` which would look as if it came from the new session, ie appearing offline to everyone including MUCs.

mod_smacks: Fix indentation Meld keeps messing up indentation when I merge and rebase...

mod_smacks: Stop stanzas from being queued on hibernation timeout This overloads that flag a bit, but it has the intended effect of stopping outgoing_stanza_filter() from queueing stanzas. Fixes a traceback because of the queue having been removed somewhere around here, since it is no longer needed. Thanks Martin for reporting

util.smqueue: Simplify compat table, fix dependent modules (thanks Martin) There was an off-by-one in the modulo calculation. Switching to a plain old array-table makes the apparent size of the queue wrong, but since some of the queue may not be available this is likely for the best.

util.smqueue: Add missing method to Teal record spec

mod_smacks: Limit queue memory consumption using new util This brings back the queue size limit that was once added, then removed because destroying the session when reaching the limit was not great. Instead, the queue wraps and overwrites the oldest unacked stanza on the assumption that it will probably be acked anyway and thus does not need to be delivered. If those discarded stanzas turn out to be needed on resumption then the resumption fails.