Remove ads from 404 page.

Change-Id: I5f5f643c409dfed02a4e44ce7dd33fe6e4d8f2da
diff --git a/_includes/header404.html b/_includes/header404.html
new file mode 100644
index 0000000..8c851d7
--- /dev/null
+++ b/_includes/header404.html
@@ -0,0 +1,17 @@
+<header>
+<div class="wrapper">
+
+      <div class="trigger">
+        {% for page in site.pages %}
+	  {% unless page.exclude %}
+          {% if page.title %}
+          <a class="page-link" href="{{ page.url | prepend: site.baseurl }}">{{ page.title }}</a>
+          {% endif %}
+	  {% endunless %}
+        {% endfor %}
+      </div>
+    </nav>
+
+  </div>
+
+</header>