Fix 206

<b>pkcs15: use 'direct' public key value</b>

pkcs15: in pubkey-info data
- introduced new 'direct' 'raw' and 'spki' members
- removed 'encoded der data' member
- in 'read-public-key' try firstly SPKI direct value
 
pkcs11:
- 'direct' data used when getting CKA_VALUE attribute of public key
    
pkcs15init:
- initialize 'raw' and 'spki' direct public key value