new patch series for author reordering code

[Dirk Hohndel]

I tried to break this out into logically independent pieces - but to connect
this as a series.  
First we add the authors member and accessors to message
Second the reordering of thread authors (still the original string based
algorithm that I used before - I couldn't quite make sense of cworth's proposed
algorithm
Third a NEWS blurb
Fourth test for the new functionality
Fifth a first simple routine to make author names easier to read - this one
undoes the typical Exchange ugliness

I think this could go into 0.3 as is. I've been using the mostly identical
previous version for about a week - the changes here are mostly cleanup based
on cworth's feedback.

I am planning to enhance the "display author names in a friendlier way" feature
in the future, capturing more cases.

/D