Load settings from an rtv configuration file.

def get_file(cls, filename=None):
        """
        Load settings from an rtv configuration file.
        """

        if filename is None:
            filename = CONFIG

        config = configparser.ConfigParser()
        if os.path.exists(filename):
            with codecs.open(filename, encoding='utf-8') as fp:
                config.readfp(fp)

        return cls._parse_rtv_file(config)