Missing argument 4 for BaseDD::BaseDD()

We are receiving this warning with PHP 5.3.3.

```
mod_fcgid: stderr: PHP Warning:  Missing argument 4 for BaseDD::BaseDD(), called in /**/wp-content/plugins/digg-digg/include/dd-manual.php on line 123 and defined in /**/wp-content/plugins/digg-digg/include/dd-class.php on line 97
```

I am calling `dd_digg_generate('Normal')` to include it in our pages.
