Add jQuery-selectBoxIt git submodule

[#44741681]
Add jquery-selectBoxIt script to haml pages
Modify SelectBoxIt styles

Add vertical line, change font, change gradients

[#44741681]
Use SelectBoxIt to create pulldown component

Instead of returning the select element, we return
a span containing the (hidden) select and the new
SelectBoxIt component.

Had to add a sizing hack to get new element to expand
appropriately given a set of text options. See

https://github.com/gfranko/jquery.selectBoxIt.js/issues/129

The $().measure function could potentially go in a
utils file.

[#44741681]
Embed fake pulldown in view for correct measuring.

Make the interactiveContainer accessible from the
interactive controller, so components can use it if
necessary.

When embedding the fake component onto the page for
measuring, use interactiveContainer so that it is
styled correctly before measuring.

[#44741681]
Update size of select box when interactive size changes

[#44741681]