Merged in feature/from-pantheon (pull request #16)

code from pantheon

* code from pantheon

wp/wp-content/plugins/wordpress-seo/src/functions.php

@@ -0,0 +1,38 @@
+<?php
+/**
+ * WPSEO plugin file.
+ *
+ * @package WPSEO\Internals
+ */
+
+if ( ! defined( 'WPSEO_VERSION' ) ) {
+	header( 'Status: 403 Forbidden' );
+	header( 'HTTP/1.1 403 Forbidden' );
+	exit();
+}
+
+use Yoast\WP\SEO\Main;
+
+if ( is_dir( WPSEO_PATH . YOAST_VENDOR_PREFIX_DIRECTORY ) ) {
+	require_once WPSEO_PATH . YOAST_VENDOR_PREFIX_DIRECTORY . '/guzzlehttp/guzzle/src/functions.php';
+}
+
+/**
+ * Retrieves the main instance.
+ *
+ * @phpcs:disable WordPress.NamingConventions -- Should probably be renamed, but leave for now.
+ *
+ * @return Main The main instance.
+ */
+function YoastSEO() {
+	// phpcs:enable
+
+	static $main;
+
+	if ( $main === null ) {
+		$main = new Main();
+		$main->load();
+	}
+
+	return $main;
+}