Introduction of the itemdelegate for mailody. That part is in charge of the display of the header. So it converts dates to readable dates, formats the size column nicely and applies the colors where needed.

That functionality is now removed from the view and the model. Also the delegate works only on the items showed, hence we increased speed dramatically, before this commit it calculated the dates/size for every item in the model, as soon as data arrived, for all items, including the invisible ones. Credits also go to Johan Thelin. Good book.