In-a-Dyn v2.9.1

Changes

• debian/ directory and packaging dropped in favor of downstream
  official packaging. Too difficult to support different versions and
  derivatives, not just Debian but also Ubuntu, etc.
• Source $INADYN_ARGS, or $INADYN_OPTS, for the command line from an
  EnvironmentFile in the systemd unit file
• Reference the README in the systemd unit file instead of home page

Fixes

• Issue #367: fix multiple hostname composition in custom providers when
  using printf(3) style format specifiers in ddns-path
• Issue #368: fix build with GCC 4.8, by Fabrice Fontaine