All modules should be named Xxx_Core for extensibility. Fixes #1458.

modules/comment/models/comment.php

@@ -17,7 +17,7 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA  02110-1301, USA.
  */
-class Comment_Model extends ORM {
+class Comment_Model_Core extends ORM {
   function item() {
     return ORM::factory("item", $this->item_id);
   }