Default crypto parameters can now be preseeded

List of parameters:
 * cipher: aes, serpent, etc.
 * keysize: 256, 192, 128 (for aes)
 * ivalgorithm: xts-plain64, cbc-essiv:sha256, etc.
 * keytype: passphrase, random
 * keyhash: sha1, sha256, etc.