Add option for plot; Increase flexibility of input args; Add comments…

[mharms]

… to script

[mdtisdall]

This is great. One small request I'd make is that the import of the pyplot lib be moved into the simplePlot function. This allows the code to run on environments where pyplot isn't installed. Perhaps getting pyplot installed and running is trivial, but I'm not a very strong python user and I've had some issues getting it configured on headless systems. I figure this way we can make the script useable in its basic, text-only form with fewer dependencies. Is that okay with you?