This commit rewrites the entire device management layer of fxlink on the
libusb side, providing new abstractions that support live/async device
management, including communication.
This system is put to use in a new TUI interactive mode (fxlink -t)
which can run in the background, connects to calculators automatically
without interfering with file transfer tools, and is much more detailed
in its interface than the previous interactive mode (fxlink -i).
The TUI mode will also soon be extended to support sending data.
Lephenixnoir