Comment 28 for bug 1466857

@Wayne, not sure whether you had 5 or 6 in mind for this one, but attached is a patch if you want to take a look at it.

Simplify Exchange Footprints dialog and add Update mode.

This commit also adds a no-selection-mode, which allows the user
to specify what gets update (through the various match modes).
The no-selection-mode is accessed via the Edit menu, although
it could also be applied to the context menu.