param defaults in script docs

[nick-youngblut]

It would help to have the parameter defaults in the script docs. Example code to automatically add defaults:

class CustomFormatter(argparse.ArgumentDefaultsHelpFormatter,
                      argparse.RawDescriptionHelpFormatter):
    pass

parser = argparse.ArgumentParser(description=desc, epilog=epi,
                                 formatter_class=CustomFormatter)

[jrober84]

Thank you very much for this! This will definitely make things easier for users. I have implemented these changes and they will be in the next version 3.1.0