Prevent redirection when in dev mode, so that we can see the debug output from each page

git-svn-id: file:///svn-source/pmgr/branches/hosted_migration_20130215@1028 97e9348a-65ac-dc4b-aefc-98561f571b83

site/app_controller.php

@@ -464,7 +464,8 @@ class AppController extends Controller {
     App::import('Helper', 'Html');
     $url = HtmlHelper::url($url, true);
 
-    if (headers_sent()) {
+    if (headers_sent() ||
+	($this->dev() && $this->Option->enabled('dev'))) {
       // If we've already sent the headers, it's because
       // we're debugging, and our debug output has gotten
       // out before the redirect.  That's probably a good