Update code for CUL Top Navigation Bar Widget

Copied and pasted the "Advanced Usage" code given for the
Top Navigation Bar Widget from the following web page:
http://cdn.cul.columbia.edu/ldpd-toolkit/widgets/
Add conditional code to handle IE 8 quirkiness

Added conditional top-padding to body -- for some reason, the CUL
widget is not able to do it.
Also do not load jquery-cul.js if IE 8, because the top navigation
widget gets all messed up.