Scan for devices improvements

[LFd3v]

Hi, there.

Some suggestions about how to improve the Scan for Devices feature:

1. Add a "re-scan" button (the know icon, a circle with and arrow) to the top right
2. The spinning circle at the center that informs the user that the scan is going on goes away once the first device is found, so the user has no feedback when the scan is actually finished. Probably it would be nice to add the spinning as an overlay or something, or just replace the "re-scan" icon to a spinning animation while it is going on, or maybe use an X to cancel the scan in the middle...

Cheers