Improvements in padding and unpadding:
- Fix an off-by-one error in ISO7816 unpadding. - Unpadding errors are not assertion failures, handle the error. - Check all the requirements of the padding scheme when unpadding.
- Fix an off-by-one error in ISO7816 unpadding. - Unpadding errors are not assertion failures, handle the error. - Check all the requirements of the padding scheme when unpadding.