Config bug when adding a 2nd expansion hub. #143

If you add a 2nd hub you have to restart the app to config it. Steps to reproduce.

1. keep UART unplugged, connect one hub
2. open config, create a new config file and scan for devices
3. close config
4. connect second hub
5. open config, create a new config file and scan for devices. only one hub will show up
6. close and relaunch app
7. open config, create a new config file and scan for devices. both hubs should show now