refactored SubPacket to SigSubPacket; added User Attribute packet and Embedded Signature Subpacket
refactored SubPacket to SigSubPacket; added User Attribute packet and Embedded Signature Subpacket

SecurityInnovation/PGPy,J08nY/PGPy,SecurityInnovation/PGPy,SecurityInnovation/PGPy,J08nY/PGPy