implement CertificateChain conversion functions
switch to asn1-types 0.1.2
reorganize module export list
add some code for CRL parsing.
add an instance of Eq for SignedExact.
properly define certificate chain functions.
WIP validation stuff.
add documentation
add documentation
misc add a line.
add a extensionDecode which use the dummy undefined parameter bounded by the same type
to use extOID before extDecode.
add specific SignedExact accessor.
make DN an instance of Ord and move x509-store to use x509 instead of certificate.
convert x509-system to x509 and x509-store
add missing files and stub things to make it compiles
add decodeSignedCertificate and decodeSignedCRL for easier decoding.
add dependency back in x509-util