Add options to command line.

def options(self, parser, env):
        """
        Add options to command line.
        """
        super(LeakDetectorPlugin, self).options(parser, env)
        parser.add_option("--leak-detector-level", action="store",
                          default=env.get('NOSE_LEAK_DETECTOR_LEVEL'),
                          dest="leak_detector_level",
                          help="Level at which to detect leaks and report memory deltas "
                               "(0=None, 1=Dir, 2=Module, 3=TestCaseClass, 4=Test)")

        parser.add_option("--leak-detector-report-delta", action="store_true",
                          default=env.get('NOSE_LEAK_DETECTOR_REPORT_DELTA'),
                          dest="leak_detector_report_delta",
                          help="")

        parser.add_option("--leak-detector-patch-mock", action="store_true",
                          default=env.get('NOSE_LEAK_DETECTOR_PATCH_MOCK', True),
                          dest="leak_detector_patch_mock",
                          help="")

        parser.add_option("--leak-detector-add-traceback", action="store_true",
                          default=env.get('NOSE_LEAK_DETECTOR_SAVE_TRACEBACK', False),
                          dest="leak_detector_save_traceback",
                          help="")

        parser.add_option("--leak-detector-ignore-pattern", action="append",
                          default=(list(filter(operator.truth,
                                               env.get('NOSE_LEAK_DETECTOR_IGNORE_PATTERNS',
                                                       '').split(','))) or
                                   ['NOSE_LEAK_DETECTOR_IGNORE']),
                          dest="leak_detector_ignore_patterns",
                          help="")