- remove command line option '--card-driver';
- instead force driver 'PIV-II' and fail if card is not a PIV card
- overhaul option parsing
- remove unused variable 'long_optind'
- make work option '--reader' ( "r:" was missing in the optstring!!!)
- bail out with usage message on all unknown/unhandled args
- correctly terminate option parsing (no infinite loop)
Extend piv-tool the same way opensc-explorer was extended. I.e.
treat the question mark given as argument to option '--card-driver'
special: list all available drivers instead of stupidly bailing out.
In contrast to opensc-tool and opensc-explorer, which are card-agnostic,
I am not sure whether the option '--card-driver' makes sense on this
card-specific tool.