Dynamically shrink footer text to fit on one line.

Fixes #3129.

Not done yet--I'm not quite sure where I can plug this into the dialog startup flow such that it **always** runs when the dialog loads, but is in run in a context where we can loop with setTimeout (so that the UI can redraw the footer text between measurements).

@shane-tomlinson any thoughts on a good place to put this code?

here's a fiddle showing the resize thingy in action: http://jsfiddle.net/vFM2v/