Still need to grab it on the room-level from the room state if possible,
otherwise just rollback to the MXID.
I also need to consider profile pictures and bridging media, and check
if the nick was present XMPP-side first, as that can and will cause
issues, especially around semi-anonymous MUCs.
Still lots of things required(like using the users JIDs whenever
possible, otherwise dropping to occupant ID), images, replies, rich data
with HTML and whatever XMPP has, etc...
There is still this fun issue with the blocking XML parser leaking
memory on pthread_cancel, I'll try to deal with that later, maybe with a
test stanza.
I also apologise for swearing in the last commit. I promise it won't
happen again, Prosody.
