Add 'Default Filters' and 'Clear Filters' buttons to new grid filters form.

tailbone/templates/newgrids/filters.mako

@@ -25,6 +25,8 @@
             <option value="${filtr.key}"${' disabled="disabled"' if filtr.active else ''|n}>${filtr.label}</option>
         % endfor
       </select>
+      ${form.tag('button', type='button', id='default-filters', c="Default Filters")}
+      ${form.tag('button', type='button', id='clear-filters', c="Clear Filters")}
     </div>
 
   ${form.end()}