PC Facade Improvements: Javadoc, launch args and usage requests.

* Increased class-level javadoc
* Renamed launch argument variables for readability and consistency.
* Now handling command-line usage requests (i.e. --help flag)

These changes were originally part of now obsolete PR #1108 and have been updated to reflect and integrate the current code. Further changes to the PC Facade had been suggested in PR #1108 but I will leave them for a separate PR.