Mark messages as read when with the pointer, but mark all messages
read if the last message is visible.
(imported from commit 4c1a928bd6966111f0f34c5207723656b5f193b9)
In a few cases the $.each was doing something imperatively that was
terser and easier to understand by using a different Underscore method,
so a few of these I rewrote.
Some code was using the fact that jQuery sets `this` in the callback to
be the item; I rewrote those to use an explicit parameter.
Some code was using $(some selector).each(callback). I converted these
to _.each($(some selector), callback).
One function, ui.process_condensing, was written to be a jQuery $.each
callback despite being in a totally different module from code using it.
I noticed this and updated the function's args.
(imported from commit bf5922a35f257c168cc09ec1d077415d6ef19a03)
Kevin Mehall
Zev Benjamin
Kevin Mehall
Scott Feeney
Tim Abbott