Add file modes to file generator
- log to /var/log/$name.{log,err}
- write pidfile in the main (not forked) process to avoid a race
  condition where 'start; status' would invoke 'status' before the daemon
  process would write its pidfile and erroneously report a failure.
- Add 'echo' logging of start/stop/status.
- use 'ping' as our daemon process; couldn't think of any other
  long-running process that was reliably on all platforms.