Add the first and last class to wp_list_pages for wordpress

wp_list_pages_add_first_last.php

function wp_list_pages_add_first_last($content) {
    $content = preg_replace('/li class\=\"/', 'li class="first ', $content, 1);
    $content_rev = strrev($content);
    $content_rev = preg_replace('/\"\=ssalc il/', ' tsal"=ssalc il', $content_rev, 1);
    return strrev($content_rev);
}
add_filter('wp_list_pages','wp_list_pages_add_first_last');