* Support unit tests on Yubikey NEO
* Test ykpiv_get_version
* Test ykpiv_import_private_key
* Test ykpiv_sign_data
* Test ykpiv_decipher_data
* Test ykpiv_change_pin
* Test ykpiv_change_puk
* Test ykpiv_get_pin_retries
* Test ykpiv_set_pin_retries
* Test ykpiv_verify
* Fix segfault when |tries| is NULL
* Fix segfault when import_private_key algorithm is wrong