Move more logic to the helper modules

- Diff view changes
-- Only show pool description changes in diff view
-- Conditionally render diff link when applicable values are changed
-- Conditionally show diff view sections when values are changed
- Show renames on index view
-- There is plenty of space
-- This wasn't shown at all for wikis
-- Having to navigate to an alternate page is unwieldy for pools
- Show "posts" as a status on pools
-- This is so all changes among versions are quantified as a status
- Standardize diff/index titles

app/views/artist_versions/_listing.html.erb

@@ -1,14 +1,13 @@
 <div id="p-<%= listing_type(:artist_id) %>-listing">
 
     <%= table_for @artist_versions, {class: "striped autofit", width: "100%"} do |t| %>
-      <% t.column "Name" do |artist_version| %>
+      <% t.column "Name", td: {class: "diff-body"} do |artist_version| %>
         <%= link_to artist_version.name, artist_path(artist_version.artist_id) %>
         <%= link_to "»", artist_versions_path(search: {artist_id: artist_version.artist_id}, anchor: "artist-version-#{artist_version.id}") %>
+        <%= artist_version_name_diff(artist_version) %>
       <% end %>
-      <% t.column "Other Names" do |artist_version| %>
-        <% if artist_version.group_name.present? %>
-          <p><b>Group:</b><br>&ensp;<%= artist_version.group_name %></p>
-        <% end %>
+      <% t.column "Other Names", td: {class: "diff-body"} do |artist_version| %>
+        <%= artist_version_group_name_diff(artist_version) %>
         <%= artist_version_other_names_diff(artist_version) %>
       <% end %>
       <% t.column "URLs", td: {class: "col-expand"} do |artist_version| %>