Wrap up initial vendor catalog batch support etc.

* Adds the ability to delete all batch rows matching current query.
* Refactors some progress factory args.
* If batch initialization fails, don't persist batch.

tailbone/templates/batch/rows.mako

@@ -7,6 +7,11 @@
         ${search.render()}
       </td>
     </tr>
+    <tr>
+      <td class="tools">
+        <p>${h.link_to("Delete all rows matching current search", url('{0}.rows.bulk_delete'.format(route_prefix), uuid=batch.uuid))}</p>
+      </td>
+    </tr>
   </table>
 
   ${grid}