CESR changes

[tweedegolf-marc]

This is an intermediate state since the new TSP spec:

• Leaves open what to do with nonconfidential data?
• Seems to have some ambiguity (e.g. dual use of XRFI)
• Has count codes that are inefficient to implement and not needed
• Some changes have impact on the upper API and these changes try to behave inside the present functionality
• Verifying a signature of a Vid introduced as a parallel relationship is tricky: since this Vid is unknown it needs to be retrieved and verified before the signature can be checked. This can only happen at the async stage. Similarly, making a signature requires the encoding function to have a handle on the new private Vid as well.