Service stopped unexpectedly but child node process doesn't

Once about every 2 months my node windows service crashes unexpectedly, usually at night so it's unlikely to be caused by load. When the service stopped, the child node process continues to run so the web service is not down.
This issue is related to #12 except that service crashing unexpectedly is my main concern. Surviving child node process is also nagging because if child process is not killed before service is restarted there is port conflict.

The issue names no files, tests, or entry points. Start by investigating the Windows service lifecycle and its child Node process behavior, with attention to reproducing the intermittent crash and restart-time port conflict. Done means the service no longer stops unexpectedly or reliably terminates its child process before restart.

Written by the indexing model from the issue text.