mod_carbons: Describe return types in a comment For similarity with mod_mam, mod_csi_simple

Merge 0.11->trunk

mod_csi_simple: Consider XEP-0353: Jingle Message Initiation important Improves experience with VoIP calls initiated via JMI Closes #1548

mod_muc_mam: Fix missing advertising of XEP-0359, fixes #1547

mod_muc_mam: Fix stanza id filter event name, fixes #1546 Nice typo

mod_presence: Send unavailable presence in current thread run `session:dispatch_stanza(pres)` enqueues processing of the stanza in the sessions async thread, but becasue the entire stream close handling is now in that thread it would process the presence after the stream and session was completely closed, leading to weird errors "sent to a resting session". We call core_process_stanza() since this is what :dispatch_stanza calls in the end.

spec/scansion/blocking: Don't send stanzas after disconnecting Probably casued by mod_scansion_record catching the unavailable presence generated by Prosody on disconnect. See #1549

mod_c2s: Run stream open and close events in async thread, fixes #1103 Enables async processing during stream opening and closing.

mod_s2s: Run stream close in async context Allows async processing during stream shutdown. Fixes potential ASYNC-01 issues, however no such issues known at the time of this commit.

mod_s2s: Improve signaling of stream open events Makes it clearer, cleaner and easier to extend.