Zeroconf

- Technically backwards incompatible - restricted netifaces dependency
version to work around a bug, see
<https://github.com/jstasiak/python-zeroconf/issues/84> for details

- Dropped Python 2.6 support
- Improved error handling inside code executed when Zeroconf object is
being closed

- Better Handling of DNS Incoming Packets parsing exceptions
- Many exceptions will now log a warning the first time they are seen
- Catch and log sendto() errors
- Fix/Implement duplicate name change
- Fix overly strict name validation introduced in 0.17.6
- Greatly improve handling of oversized packets including:
- Implement name compression per RFC1035
- Limit size of generated packets to 9000 bytes as per RFC6762
- Better handle over sized incoming packets
- Increased test coverage to 95%

- Many improvements to address race conditions and exceptions during
ZC() startup and shutdown, thanks to: morpav, veawor, justingiorgi,
herczy, stephenrauch
- Added more test coverage: strahlex, stephenrauch
- Stephen Rauch contributed:
- Speed up browser startup
- Add ZeroconfServiceTypes() query class to discover all
advertised service types
- Add full validation for service names, types and subtypes
- Fix for subtype browsing
- Fix DNSHInfo support

- Fixed OpenBSD compatibility, thanks to Alessio Sergi
- Fixed race condition on ServiceBrowser startup, thanks to gbiddison
- Fixed installation on some Python 3 systems, thanks to Per Sandström
- Fixed "size change during iteration" bug on Python 3, thanks to
gbiddison

- Fixed support for Linux kernel versions \< 3.9 (thanks to Giovanni
Harting and Luckydonald, GitHub pull request \26)