Removed daemon support from Sparkplug.

Self-daemonizing services considered harmful. Please use a daemon system more modern than SysV init; upstart, systemd, daemontools, foreman, and supervisord all understand non-daemonizing processes well, and they have some nice process-management properties.

Plus, the daemon-support code never worked well.

This will be a breaking change to the shell API and to user expectations. 2.0 or bust.