Fixed Section to evaluate size constraints against the actual
"small" media query rather than specifying the size via a
setting in javascript.  This prevents all kinds of strange
behavior caused by scroll bars being included in the media
query width but not accounted for in our code.  See the
following for more info:

http://www.456bereastreet.com/archive/201301/media_query_width_and_vertical_scrollbars/
Merge pull request #2755 from seantimm/2755-SectionBreakpoint

Section js breakpoint different from css breakpoint