Progress: controller program, restructure some of f*_execute functionality, and add...

Progress: controller program, restructure some of f*_execute functionality, and add or update documentation.

For the controller program:
- add "freeze", "thaw", "pause", and "resume".
- improve simulation to actually perform an execute, but with a stub execution (an empty bash script).
- print more information when performing the stubbed simulation.
- simulation should not stop on errors when simulating, there are a number of cases where stopping is still happening.
- add a microsleep during the stubbed execution to better simulate synchronous vs asynchronous behavior.
- The F_schedule is no longer being returned from the child process, do not treat it as a child exit state.
- add more documentation.