Suggest Using Response Code of 301 for Redirects

Great module, really looking forward to this developing. Checking through other URL shorteners, the standard approach seems to be using 301 as the HTTP Response Code. As I understand it, good practice for SEO.

From http://api.drupal.org/api/function/drupal_goto/6 the default setting for drupal_goto() is to use 302. What about updating line 25 of drupal_goto() so a 301 code is used instead:

drupal_goto($orig_url, NULL, NULL, 301);