Adds a meta box to the Edit Page page where you can set to show or exclude the page from page listings.
if (! class_exists('IM8ExcludePages'))
get_excluded_pages(credits go to blizam for reporting this)
enable_im8_exclude_pagesfunctions to individually disable and enable the plugin filter (e.g., if you want to exclude several pages from your menu, and include them in your sitemap)