Asn1crypto

- Fixed `cms.CMSAttributes` to be a `core.SetOf` instead of `core.SequenceOf`
- `cms.CMSAttribute` can now parse unknown attribute contrustruct without an
exception being raised
- `x509.PolicyMapping` now uses `x509.PolicyIdentifier` for field types
- Fixed `pdf.RevocationInfoArchival` so that all fields are now of the type
`core.SequenceOf` instead of a single value
- Added support for the `name_distinguisher`, `telephone_number` and
`organization_identifier` OIDs to `x509.Name`
- Fixed `x509.Name.native` to not accidentally create nested lists when three
of more values for a single type are part of the name
- `x509.Name.human_friendly` now reverses the order of fields when the data
in an `x509.Name` was encoded in most-specific to least-specific order, which
is the opposite of the standard way of least-specific to most-specific.
- `x509.NameType.human_friendly` no longer raises an exception when an
unknown OID is encountered
- Raise a `ValueError` when parsing a `core.Set` and an unknown field is
encountered

- Added support for the TLS feature extension from RFC 7633
- `x509.Name.build()` now accepts a keyword parameter `use_printable` to force
string encoding to be `core.PrintableString` instead of `core.UTF8String`
- Added the functions `util.uri_to_iri()` and `util.iri_to_uri()`
- Changed `algos.SignedDigestAlgorithmId` to use the preferred OIDs when
mapping a unicode string name to an OID. Previously there were multiple OIDs
for some algorithms, and different OIDs would sometimes be selected due to
the fact that the `_map` `dict` is not ordered.

- Fixed a bug generating `x509.Certificate.sha1_fingerprint` on Python 2

- Added the `x509.Certificate.sha1_fingerprint` attribute

- Backwards compatibility break: the native representation of some
`algos.EncryptionAlgorithmId` values changed. `aes128` became `aes128_cbc`,
`aes192` became `aes192_cbc` and `aes256` became `aes256_cbc`.
- Added more OIDs to `algos.EncryptionAlgorithmId`
- Added more OIDs to `cms.KeyEncryptionAlgorithmId`
- `x509.Name.human_friendly` now properly supports multiple values per
`x509.NameTypeAndValue` object
- Added `ocsp.OCSPResponse.basic_ocsp_response` and
`ocsp.OCSPResponse.response_data` properties
- Added `algos.EncryptionAlgorithm.encryption_mode` property
- Fixed a bug with parsing times containing timezone offsets in Python 3
- The `attributes` field of `csr.CertificationRequestInfo` is now optional,
for compatibility with other ASN.1 parsers

- Correct `core.Sequence.__setitem__()` so set `core.VOID` to an optional
field when `None` is set