add link to main post version listing from post version subnavbar

app/views/post_versions/_secondary_links.html.erb

@@ -3,6 +3,7 @@
     <li><%= link_to "Posts", posts_path %></li>
     <li><%= link_to "Upload", new_upload_path %></li>
     <li><%= link_to "Search", search_post_versions_path %></li>
+    <li><%= link_to "Changes", post_versions_path %></li>
     <li><%= link_to "Help", wiki_pages_path(:title => "help:posts") %></li>
   </menu>
 <% end %>