HTTP-Schema independent URI

I’ve got a small improvment suggestion:

in functions.php change the link to googleapis to a schema-independent version, like

wp_enqueue_style( 'fonts', '//fonts.googleapis.com/css?family=Lusitana|Droid+Sans' );

or

$schema = (is_ssl() == TRUE) ? 'https' : 'http';
wp_enqueue_style( 'fonts', $schema.'://fonts.googleapis.com/css?family=Lusitana|Droid+Sans' );

That way it won’t break the site encryption and prevent error messages that the site is only partly encrypted.