Move login check in inc/mod/auth.php to a function

This allows pages like create.php to not include inc/mod/pages.php while still being able to use the mod auth functions (like generating salts and passwords)

mod.php

@@ -12,6 +12,8 @@ require_once 'inc/mod/auth.php';
 if ($config['debug'])
 	$parse_start_time = microtime(true);
 
+check_login(true);
+
 $query = isset($_SERVER['QUERY_STRING']) ? rawurldecode($_SERVER['QUERY_STRING']) : '';
 
 $pages = array(