Customizer: Gravefully handle cookie expipration. Prompt for log in in the preview. Props ocean90, koopersmith, nacin. fixes #20876

git-svn-id: https://develop.svn.wordpress.org/trunk@21031 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/script-loader.php

@@ -305,6 +305,7 @@ function wp_default_scripts( &$scripts ) {
 		'saved'     => __( 'Saved' ),
 		'cancel'    => __( 'Cancel' ),
 		'close'     => __( 'Close' ),
+		'cheatin'   => __( 'Cheatin’ uh?' ),
 	) );
 
 	if ( is_admin() ) {