Changing EC Public Key format in PuKDF from raw to spki

This patch changes the format in which EC Public Keys are stored as direct value in the PuKDF structure. PKCS#15 allows raw (ECPoint) and spki format.

As raw does not preserve domain parameter, the EC_PARAMS for an EC Public Key are lost during the encoding of a newly generated EC key pair.

This patch contains code from Douglas's previous EC patch (Encoding AlgorithmInfo and SPKI).

This patch might affect cards that support storing the EC Public Key (most notably the myeID card). Please carefully test with these cards.