This reverses the removal of the "Mark messages as read" preference in
commit e7247d6d60.
I apparently misjudged the popularity of this preference, as there's
been a surprising amout of backlash and confusion as to its removal on
the mailing list, IRC channel, and various distro-support forums.
So, "mea culpa" for removing that one. Haven't heard a peep about the
other removed preferences, however, so they will stay gone.
0ae8e9e7b7