Always put a space between RFC and number
Provide an RFC 3394 AES key wrapping algorithm

This also introduces an EncryptionError exception.
Allow speciying an initial value for key wrapping
Implement padding as specified in RFC 5649

This adds a pad argument with which padding can be forced or disabled.
Support kw-aes128, kw-aes192 and kw-aes256

This adds support for key unwrapping using the RFC 3394 or RFC 5649
algorithm if the PSKC file uses this.