- Stricter argument parsing, to help user avoid configuration surprises.
- Ask kernel to detach USB HID driver with libusb 0.1 too.
- Properly reject keys (-a) with upper case hex, instead of just ignoring
those bits.
- Really check Yubikey compatibility when setting options.
- Pretty-printer did not handle bit overloaded cfgflags.
It is better now, but not perfect.
- Fixes to make it work under Windows.