restyle feedback tab

related to <a href="https://ebi-forecast.igb.illinois.edu/redmine/issues/2307">redmine 2307</a> and <a href="https://ebi-forecast.igb.illinois.edu/redmine/issues/2306">2306</a>
Changed color, size and added script to hide tab. Changes can be viewed at http://pecandev.igb.illinois.edu/jk/ (login:testuser, password:123456).