Added config option to enable or disable file uploads with notices.

config.php.sample

@@ -222,5 +222,6 @@ $config['sphinx']['port'] = 3312;
 // $config['attachments']['file_quota'] = 5000000;
 // $config['attachments']['user_quota'] = 50000000;
 // $config['attachments']['monthly_quota'] = 15000000;
+// $config['attachments']['uploads'] = true;
 
 // $config['oohembed']['endpoint'] = 'http://oohembed.com/oohembed/';