When in debug mode, previously an explicit `blueslip.error()` call
would not display the original stack trace of the error, making
debugging difficult.
This isn't perfect, in that it seems to display some tracebacks
multiple times, but at least the trace is available.
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)
Steve Howell
Arpith Siromoney
Tim Abbott
Jason Michalski
Zev Benjamin
Tim Abbott
Scott Feeney
Tim Abbott