Update GreedyNav to use flexbox instead of display: table

- ref #836

_includes/masthead.html

@@ -2,9 +2,8 @@
   <div class="masthead__inner-wrap">
     <div class="masthead__menu">
       <nav id="site-nav" class="greedy-nav">
-        <button><div class="navicon"></div></button>
+        <a class="site-title" href="{{ '/' | absolute_url }}">{{ site.title }}</a>
         <ul class="visible-links">
-          <li class="masthead__menu-item masthead__menu-item--lg"><a href="{{ '/' | absolute_url }}">{{ site.title }}</a></li>
           {% for link in site.data.navigation.main %}
             {% if link.url contains 'http' %}
               {% assign domain = '' %}
@@ -14,6 +13,7 @@
             <li class="masthead__menu-item"><a href="{{ domain }}{{ link.url }}">{{ link.title }}</a></li>
           {% endfor %}
         </ul>
+        <button><div class="navicon"></div></button>
         <ul class="hidden-links hidden"></ul>
       </nav>
     </div>