Add previous projects

Author: kjurdzinski

_layouts/default.html

@@ -47,6 +47,7 @@ <h1 id="logo"><a href="index.html">EnvGen</a></h1>
                                 <li><a href="/whoweare.html#main">People</a></li>
                                 <li><a href="/#press">Press Releases</a></li>
                                 <li><a href="/projects.html#main">Projects</a></li>
+								<li><a href="/old_projects.html#main">Previous Projects</a></li>
                                 <li class="submenu opener"><a href="/#cta">Software</a>
                                 <ul>
                                     <li><a href="https://github.com/BinPro/CONCOCT">CONCOCT</a></li>