Bugfix: PID and PID file should account for multiples during process execution.

Bugfix: PID and PID file should account for multiples during process execution.

I forgot all about needing to do this so I am considering this a bug.

Each process may execute multiple Actions.
Each Action has its own PID.

In the case of foreground (synchronous) execution, having only a single PID and PID file path on the Process structure is not a problem.
When with PID file (asynchronous) execution operates, multiple PIDs (and respective PID files) may exist for any single Process structure.

Use an array of PIDs and PID file paths.