Add show actions for note, artist, artist commentary versions.

Add these endpoints:

* /note_versions/1234
* /artist_versions/1234
* /artist_commentary_versions/1234

This is so the /ip_addresses listing can link to these endpoints.

app/controllers/artist_commentary_versions_controller.rb

@@ -5,4 +5,11 @@ class ArtistCommentaryVersionsController < ApplicationController
     @commentary_versions = ArtistCommentaryVersion.paginated_search(params)
     respond_with(@commentary_versions)
   end
+
+  def show
+    @commentary_version = ArtistCommentaryVersion.find(params[:id])
+    respond_with(@commentary_version) do |format|
+      format.html { redirect_to artist_commentary_versions_path(search: { post_id: @commentary_version.post_id }) }
+    end
+  end
 end