Show peer OTR key for old messages

[infinity0]

When a contact goes offline, jackline will prefix the older messages with the XMPP resource. It would be good to show the OTR key that those messages were authenticated as, too.

If this makes the prefix too long, you could instead show it once, and wrap the relevant messages in a box:

--- start of previous session with ($OTR_key $XMPP_resource) ---
$time0 $message0
$time1 $message1
etc 
--- end of previous session with ($OTR_key $XMPP_resource) ---

[hannesm]

not convinced that this will be useful for most users... and it'll be more output.. there's also not always the case that you're chatting with a single resource, but maybe exchange one message with one resource, then moving to a different resource, etc.

[infinity0]

the resource that you think you're chatting with can be faked, it's the key that actually identifies the peer who is chatting.

you could instead put it in this line: ***OTR*** encrypted connection established (ssid [xx] xx) - add the full key fingerprint in here, then it's much more obvious who i'm chatting with, if they end the conversation before i get a chance to do /otr info or /fingerprint.

[cfcs]

I think this is a sensible idea.
Colorizing them differently (as an additional visual cue) would also be nice.