Enhanced ECC handling  - Part 2

An EC point when used with PKCS#11 and PKCS#15 is encoded as an OCTET STRING.
It is stored as a OCTET STRING in sc_pkcs15_pubkey_ec.  But when an EC point
is in a SPKI the unencoded string is encoded in a BIT STRING thus there are
two ways to encode an ECpoint.

All the sc_pkcs15_encode_pubkey_* routines will only return a predetermined
encoding. sc_pkcs15_encode_pubkey_ec was modified to accept a format parameter.
   0 - return the OCTET STRING,
   1 - return the unencoded byte array.
the caller can then encode it as needed.

sc_pkcs15_encode_pubkey_ec now takes a sc_pkcs15_pubkey parameter thus giving
it access to the the algorithm_id and its parameter.

For backward compatability, sc_pkcs15_encode_pubkey now calls
sc_pkcs15_encode_pubkey_ext that also has a format parameter.

sc_pkcs15_encode_pubkey_spki nows calls sc_pkcs15_encode_pubkey_ext
with format=1.