First 0.8 beta

This is the first beta release of the smart card application to be used during the IRMA Kerckhoffs pilot (https://www.irmacard.org/pilot/).

This release includes a rewrite of the earlier idemix implementation on MULTOS (https://github.com/credentials/idemix_multos). The cryptographic part is basically the same but the application logic has been rewritten to include state and support authentication and secure messaging (these last two features are not used at this point). Also the rewrite should make maintenance of the codebase easier.