[dev] Order by Thread

[Chuck Hagenbuch]

Quoting Andreas Dahlén <andreas@dahlen.ws>:

> This change realy makes sense for me. But I think that, as default, 
> should Subject be emphasized, i.e. Thread is only emphasized when 
> sorted on thread.

I'm happy to change this, but wonder if others agree/disagree?

-chuck

--
Charles Hagenbuch, <chuck@horde.org>
"A dream which helps you to live your reality with dignity
 and justice is a good dream." - Tariq Ramadan