This app takes data coming in on any of the normal USB endpoints
like CDC and FIDO (or CCID) and outputs the data on the DEBUG
endpoint.
Using the scripts (tkey_to_udp_linux.py, tkey_to_udp_win.py) in
QEMU (tk1 branch) under tools/tk1, the data from the DEBUG
endpoint can be read and sent over the network to the script
udp_to_qemu_linux.py that feeds it to QEMU.
