Better init system integration, with the following new command line options:
- --daemon
- Supersedes now-deprecated 'daemon' config file option.
- --no-daemon
- Overrides now-deprecated 'daemon' config file option.
- --version
- Outputs version number.
- --test-config
- Tests configuration file.
- --user <user>[:<group>]
- Drop to the user and group named <user> and <group> retaining essential capabilities. Group defaults to <user>'s if not specified.
Synchronizes with systemd on startup as a 'notify'-type service.