removed link to wiki from nav bar

Author: gonsie

_includes/header.html

@@ -18,7 +18,6 @@ <h1>
         <img width="19px" height="19px" src="{{ site.baseurl }}/images/github.png">
       </a>
       <a class="page-link" href="https://github.com/ross-org/ROSS/issues">Issues</a>
-      <a class="page-link" href="https://github.com/ross-org/ROSS/wiki">Wiki</a>
       <a class="page-link" href="http://ross-org.github.io/ROSS-docs/docs/html/">Doxygen</a>
       </span>
     </nav>