Fix footer

- After adding padding and margin to the paragraph the footer was
no longer working properly.
- Paragraph in the footer changes to a div.

templates/_footer.twig

         <div id="footer">
             <div class="wrap">
-                <p class="center copyrights dark-bg">
+                <div class="center copyrights dark-bg">
                     <br>Copyright © 2007-2017
                     <br>
                     <i class="fa fa-github" aria-hidden="true"></i> <a href="https://github.com/simplesamlphp/simplesamlphp">SimpleSAMLphp</a>
-                </p>
+                </div>
                 <div class="logo-footer-right">
                     <div class="logo-footer">
                         <img class="pure-img" src="/{{ baseurlpath }}resources/icons/ssplogo-fish-small.png" alt="Small fish logo">