Adds post title as a value to WP's body_class and post_class

add_post_title_class.php

<?php

function add_post_title_class($classes) {
  global $post;

  if ($postTitle = sanitize_title($post->post_title)) {
    $classes[] = $postTitle;
  }

  return $classes;
}

add_filter('body_class', 'add_post_title_class');
add_filter('post_class', 'add_post_title_class');