mdnsd v0.12

IPv6 support, including a lot of fixes and cleanup again from the team
at devolo AG.

Changes

• libmdnsd, mquery, and mdnsd: add support for IPv6 AAAA records,
  including display in mquery, by Florian Zschocke, devolo AG
• mdnsd: add -H hostname support, for testing purposes mainly
• mquery: add -l debug support
• mquery: Display every answer we get when in mdnsd-scan mode
• Initial support for test framework, including unit testing w/ cmocka
• Add support for disabling installation of man pages
• Add support for building without mquery

Fixes

• Fix #11: port to other UNIX systems, currently tested on the following
  operating systems, except Linux, should also work on later versions:
  • FreeBSD 13
  • NetBSD 9.1
  • OpenBSD 6.8
  • DragonFly BSD 5.8
  • SunOS solaris 5.11 omnios-r151034
• Fix #49: various typos in log messages
• Fix #52: double free, introduced in v0.11
• Fix #55: mDNS conflict check, fixed by Florian Zschocke, devolo AG
• Fix #56: parsing of A record from packet must maintain network byte
  order, found and fixed by Florian Zschocke, devolo AG
• Fix #65: libmdnsd: Make SPRIME actually a prime number, found and
  fixed by Florian Zschocke, devolo AG
• Fix #74: fix segfault when mdnsd interface is removed