table builder: fix various incorrect css classes.

Change calling convention to explicitly indicate whether the attributes
are for the <th> element or the <td> element. Fixes various cases where
the two were mixed up.

* Fix .col-expand classes not being set correctly on the /post_versions,
  /pool_versions, and /notes pages.

* Fix .updater and .updated-at classes not being set correctly on the
  /forum_topics page.

* Fix the name param being ignored (noticeable in the post count field
  on the /tags page).

* Don't pass empty string when column has no name.

app/views/users/index.html.erb

@@ -3,7 +3,7 @@
     <h1>Users</h1>
 
     <%= table_for @users, width: "100%" do |t| %>
-      <% t.column "" do |user| %>
+      <% t.column do |user| %>
         <% if CurrentUser.is_admin? %>
           <%= link_to "Edit", edit_admin_user_path(user) %>
         <% end %>