Well, it's exactly what it says: Work in progres...
Widget for this plugin is still in development, and that's the reason for the message, nothing is done yet in the widget part. As you can see, version of the plugin is still not come to 1.0.0, and is still marked as Alpha, meaning that a lot of work needs to be done.
Currently, I am working on version 0.6.0 Alpha, and this one will be out in the next 1 or 2 days. It will add some important fixes, more changes and improvements and also a shortcode support.
Widget will be next step, and is expected for version 0.7.0 Beta. This version will be out in the next 7 or 8 days.
Thanx for the post, and if you have any suggestion for the plugin features, plaeas leave me a message, email or post on my website.