Fixed incorrect implementation of key stuff: curve25519 and ed25519 keys are now generated separately, the pcp-proprietary "derived key" feature has been dropped.
dropped "derived key feature", pk-encryption now uses a random keypair on the sender side, puts the public part of it into the encrypted output and drops the keypair, no more key-id will be sent over the wire, be it hashed or whatelse.
modifications to match recent changes. that's just preparation of more changes towards PBP-Compatibility. Current state is UNSTABLE. See TODO for details whats left to do.