[Geary] conversation list sorting criteria

[Federico Bruni <fede inventati org>]

As far as I understand, the conversation list is sorted by _receiving_ 
date/time.
This means that if I reply to an old conversation, this conversation 
will stay in the bottom of the list until someone replies to my message.

I'm used to a different behaviour, as in Gmail, where sent messages are 
taken into account when sorting conversations.
I like this approach, because I want recent conversations to stay on 
top and IMO sent messages count as much as received messages.

What's your feeling about it?