Add a way to enumerate the connected devices

[edorfaus]

The program requires that the user specify which device to use, by its device path.

It should have a way of listing the devices on the system, including the device path for each, so that the user can know which path to use.

[JohnnyBackflip]

No matter what path I try I always get the error "Could not open device:" I tried everything I know and googled 20+ hours to find out whats the correct path but it still doesnt work.