- Fix license
- Update to 4.4.4:
* Copyright notice extended to the year 2018
* Fixed short local key expansion at 3DES key localization
implementation.

- Update to 4.4.3:
* Migrated references from SourceForge
* Added missing SHA2 support for Blumenthal key localization
* Fixed named bits handling at rfc1902.Bits
* Fixed missing SmiError exception class at pysnmp.proto.rfc1155
* Fixed SNMP v1->v2c PDU proxy -- error-status & error-index fields
from v1 PDU get copied over to v2c PDU in addition to the exception
sentinels being set
- Update to 4.4.2:
* The pysnmp version being used gets exposed to the MIB modules
via the `MibBuilder` instance
* The .setObjects() method of the SMI types now accepts
`append=False` parameter to let the caller adding more
than 255 elements over the course of multiple calls
* Added support for some more missing fields of SMIv2 MACRO types
* Example scripts rearranged in a way that IPv6 requirement is
clearly encoded in the script's name
* Fixed SNMPv2-SMI.NotificationType to expose .set/getReference()
instead of .set/getRevision() which should not be there in the
first place
* Fixed non-implied-OID encoding in SNMP table indices
* Fixed inconsistent SNMPv3 discovery and retrying algorithm
- Update to 4.4.1:
* HMAC-SHA-2 Authentication Protocols support added (RFC-7860)