Code prior to this commit was functionally working, but semantically
flawed — returning false does not short-circuit _.each like it does with
$.each. It now uses _.every, as suggested by Steve.
In addition I renamed the function to be more descriptive, added a
comment, and eliminated needless double negation.
(imported from commit b0666dfa01b2677b4eaf577fe9ced90ed0db2438)
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)