Noticed that this module is not added to the admin menu upon enabling due to the incorrect menu type. Furthermore this should be nested under a menu item - the code below fixes this and puts it under the "Development" section.
/**
* Implement menu hook.
*
* @access public
* @return void
*/
function cdnjs_menu() {
$items = array();
$items['admin/config/development/cdnjs'] = array(
'title' => 'CDN JS',
'page callback' => 'drupal_get_form',
'page arguments' => array('cdnjs_settings'),
'access arguments' => array('administer site configuration'),
'type' => MENU_NORMAL_ITEM,
);
return $items;
}