altos/chaoskey: Add another USB endpoint to read raw data

altos/chaoskey: Add another USB endpoint to read raw data

This replaces having the single output switch based on a pin value and
allows us to box the device and still fetch raw data.

For now, this will use a special libusb2 program, ao-chaosread, to
pull bits as I haven't figure out how to make linux provide two
/dev entries for one USB device.

Signed-off-by: Keith Packard <keithp@keithp.com>