Parses arguments, returns ``(options, args)``.

def parse_args(args=None):
    '''Parses arguments, returns ``(options, args)``.'''
    if args is None:
        args = sys.argv

    parser = argparse.ArgumentParser(description='MicroDrop plugin '
                                     'dependencies installer',
                                     parents=[INSTALL_REQUIREMENTS_PARSER])

    return parser.parse_args()