Added End Exam Button for Menu Mode

Issue #917 - added an end exam button for menu mode in Numbas

Author: mthakurt

themes/default/templates/menu.html

@@ -49,4 +49,7 @@ <h1 id="infopage-menu-header" data-bind="html: exam.settings.name"></h1>
         </tbody>
     </table>
 </nav>
+<!-- End Exam Button -->
+<button class="btn btn-danger navbar-btn center-block" id="endBtn" data-localise="control.end exam" data-bind="click: Numbas.controls.endExam"></button>
+
 <button class="btn btn-default navbar-btn center-block thin-button" type="button" data-bind="click: Numbas.display.showStyleModal" data-localise="control.style options"></button>