- [server] Added a major new feature that allows fwknopd to easily
      integrate with third-party devices and software. This done through the
      addition of a generic "command open" and "command close" capability, and
      a set of variable substitutions are supported such as '$SRC', '$PORT',
      and '$PROTO'. This feature is designed to allow the user to switch out
      the default firewall - iptables, firewalld, ipfw, or PF - for something
      complete different. For example, here is a write-up on using this feature
      to integrate SPA operations with ipset:

        https://cipherdyne.org/blog/2015/12/single-packet-authorization-and-third-party-devices.html

    - [server] (Jonathan Bennett) Added new access.conf directives
      '%include <file>' and '%include_folder <directory>'. This allows more
      access stanzas to be defined in other locations in the filesystem, and
      this can be adventageous in some scenarios by letting non-privledged
      users define their own encryption and authentication keys for SPA
      operations. This way, users do not need write access to the main
      /etc/fwknop/access.conf file to change keys around or define new ones.
    - [server] Bug fix to not send the TCP server a TERM signal even when it is
      not running when fwknopd receives a HUP signal.
    - [libfko] Bug fix for a crash that could be triggered in
      fko_set_username() when a username that is 64 chars or longer is
      specified. This crash cannot be triggered in fwknopd even if an SPA
      packet contains such a username however due to additional protections in
      the SPA decoding routines. Further, this bug does not apply to the main
      fwknop client either because the maximal username size is truncated down
      below 64 bytes. Hence, this bug only applies to client-side software that
      is directly using libfko calling the fko_set_username() function.
    - [test suite] Code coverage is now at 90.7% counted by lines. The complete
      coverage report for the 2.6.8 release is available here:

        https://www.cipherdyne.org/fwknop/lcov-results/