Header title for list and hashtags

Increase the title header for lists to match single pages. Add a hashtag
for taxonomies.

layouts/_default/list.html

@@ -5,7 +5,8 @@
         <div class="row">
           <div class="col-lg-8 col-lg-offset-2 col-md-10 col-md-offset-1">
             <div class="page-heading">
-              <h2>#{{ .Title }}</h2>
+              <h1>{{ if .Data.Singular }}#{{ end }}{{ .Title }}</h1>
+              <hr class="small">
             </div>
           </div>
         </div>