Move the code for adding/removing classes from Panels to CTools

Panels has this super useful code that other modules can use to add or remove classes to the body tag:

/**
 * Remove default sidebar related body classes and provide own css classes
 */
function panels_preprocess_html(&$vars) {
  $panel_body_css = &drupal_static('panel_body_css');
  if (!empty($panel_body_css['body_classes_to_remove'])) {
    $classes_to_remove = explode(' ', $panel_body_css['body_classes_to_remove']);
    foreach ($vars['classes_array'] as $key => $css_class) {
      if (in_array($css_class, $classes_to_remove)) {
        unset($vars['classes_array'][$key]);
      }
    }
  }
  if (!empty($panel_body_css['body_classes_to_add'])) {
    $vars['classes_array'][] = check_plain($panel_body_css['body_classes_to_add']);
  }
}

I think it would be really nice if this functionality was available for many more modules to use in CTools. I've adapted my custom functions and converted them to CTools.