Use flex instead of float for the list of profiles

[acalog]

Fixes #{issue-number}.

Changes proposed in this pull request

Required pull requests to merge (usually a pull request on Foundation or a plugin)

Test sites

Clone these sites to your sandbox, and review them briefly. Does everything work as expected?

• Kitchen Sink Site http://10up-responsi.cms-devl.bu.edu/kitchensink/
• BU Landing Pages http://10up-responsi.cms-devl.bu.edu/bu-landing-pages/
• BU Banners http://10up-responsi.cms-devl.bu.edu/bu-banners/
• Faculty Model Site (color palettes) http://10up-responsi.cms-devl.bu.edu/facultymodel/
• BU Bands (light custom CSS) http://10up-responsi.cms-devl.bu.edu/bands/
• Data Sciences (complex custom CSS) http://10up-responsi.cms-devl.bu.edu/cds-faculty/
• Provost Advising (child theme) http://10up-responsi.cms-devl.bu.edu/advising/

Review checklist

• I have tested my changes in my sandbox on Responsive Framework and at least one child theme.
• I have tested any new filters or action hooks I have introduced in a child theme to ensure they work correctly.
• I've reviewed the contribution guidelines.
• I've updated CHANGELOG.MD with a brief explanation of the changes in this pull request in the unreleased section.
• My code follows BU Coding Standards.