Description of App
Franz is a free messaging app/former Emperor of Austria and combines chat & messaging services into one application. He currently supports Slack, HipChat, Facebook Messenger, Telegram, WhatsApp, Google Hangouts, Skype and Grape. You can download Franz for Mac and he is soon coming to Windows as well.
The app is not very usable at all. I could not even add a service to test. I contacted the dev via twitter so we'll see.