Add some SEO features to roots_wp_title()

Now <code>roots_wp_title()</code> displays left position of separator and sitename correctly. Title of page with search results inform us about total matches found, or "nothing found". Page title of date based archives and author archive in readable format. Title contains terms and taxonomies in hierarchy view (e.g. <em>Term - Taxonomy - Sitename</em>). Add support pagination: <code>$paged</code> & <code>$page</code> (e.g. <em>Category - Page 7 - Sitename</em>). Front-page title contains Sitename and Description. Updated language POT file.