updated doc for gnutls_pkcs12_simple_parse()
tests: remove test for nettle's pbkdf2; this is tested in nettle
pkcs12: Allow verification with structures that support other than HMAC-SHA1 MACs.
tests: test the decoding of a PKCS #12 structure with SHA256 MAC
tests: updated string to keys tests for new internal API
pkcs12: added gnutls_pkcs12_mac_info to obtain information on the MAC
certtool: --p12-info will provide information on the MAC algorithm
doc update
pkcs12: added gnutls_pkcs12_generate_mac2()

That allows a choice on the MAC algorithm to be used.
tests: check gnutls_pkcs12_generate_mac2()
doc update