corrected ie9 and mobile bugs

- ie9 hover on main nav is no longer green
- recently updated links are now 17px
- recently updated section has been given top padding on mobile to
separate it from main content
- background gradient has been removed from footer
- elsevier logo pagging bug is fixed on mobile
- all footer elements are center aligned on mobile
- "load more" button is green, to match the "view more" buttons
- stream item meta data is now stacked and left aligned on mobile, to
avoid date wrapping multiple lines
- topbar background has noise applied to match the rest of the page
- topar, when fixed, has a slight drop shadow to set it apart from the
other elements