Support for iptables '--wait' and improved systemd/journald logging

This release:

1. Adds support for calling iptables' --wait and --wait-seconds options, using the new --iptables-wait and --iptables-wait-seconds options respectively
2. Adds automatic detection of systemd/journald logging and improved logging in this scenario (thanks to @riton)
3. Removes limitation that the ingress network cannot be >/24
4. Documents the automated testing procedure using RunCVM
5. Minor bugfixes and documentation improvements

Full changelog:

2e8d92b Document automated testing procedure
b7f58db Support for calling iptables' --wait and --wait-seconds options
0676caf Bump minor version and fix formatting for consistency
0df1c86 Adapt log format if journald is detected
54bde9c Updated usage to better explain the service and port whitelisting options
0281837 Updated README.md
d999aae Corrected abbreviated name 'dind' to 'dird'
8b35154 Add instructions for installing the example systemd unit
7a9dfa2 Updated script permissions to 755
747e53d Explicitly inspect network ingress
f761a8d Remove limitation that the ingress network cannot be >/24