MINOR: removed tiny sliver of plus symbol from the minus styling.
MINOR: fixed width of Facebook widget
MINOR: added if statement to slider subheading
MINOR: fixed the phone number links in the footer
MINOR: added retina logo for header
BUGFIX: fixed issues with the caption on the homepage slider
BUGFIX: fixed errors thrown for slider due to upgrade regressions
ENHANCEMENT: styling and layout fixes / adjustments