v5.1.0

• Add support for core WordPress HTML5.
• Add support for responsive iframes ported from the twenty eleven theme.
• Remove IE support defaults.
• Add CSS reset.
• Add align-wide and automatic-feed-links support.
• Add set_post_thumbnail_size ported from the twenty eleven theme.
• Add support for comment reply for threads.
• Remove from wp_head actions rsd_link, wlwmanifest_link, and wp_generator.