RepoStatistics should have an option to ignore whitespace changes

[briandk]

Pass a -w flag to git log.

The easiest way is to add an argument to the argument parser

def parseCommandLineArguments(self):
        parser = argparse.ArgumentParser()
        parser.add_argument("repo_path", help="Path to the repo of interest")
        parser.add_argument("--since", help="the beginning of the time interval of interest")
        parser.add_argument("--until", help="the endpoint of the time interval of interest")
        parser.add_argument("-w", help="Ignore whitespace changes")
        return parser.parse_args()