Form constructor for administering a single book's hierarchy.
$node: The node of the top-level page in the book.
function book_admin_edit($form, $form_state, $node) {
drupal_set_title($node->title);
$form['#node'] = $node;
_book_admin_table($node, $form);
$form['save'] = array(
'#type' => 'submit',
'#value' => t('Save book pages'),
);
return $form;
}