Returns the absolute file path of the given [relative] file path
        to either this script or to the config file.

        May throw a RuntimeError if quit_on_error is True.

        :param str rel_file_path: relative file path
        :param bool quit_on_error: determines if the script may throw an
                                   exception
        :return str: absolute file path of the given relative file path
        :raises RuntimeError: if the file path does not exist and
                              quit_on_error is True

def get_abs_file_path(self, rel_file_path,
                          quit_on_error=None, check_relative_to_path=True):
        """
        Returns the absolute file path of the given [relative] file path
        to either this script or to the config file.

        May throw a RuntimeError if quit_on_error is True.

        :param str rel_file_path: relative file path
        :param bool quit_on_error: determines if the script may throw an
                                   exception
        :return str: absolute file path of the given relative file path
        :raises RuntimeError: if the file path does not exist and
                              quit_on_error is True
        """
        if self.cfg_file_path is not None and \
                check_relative_to_path and \
                not self.cfg.section('Files')['relative_to_start_processes_file']:
            script_dir = os.path.dirname(self.cfg_file_path)
        else:
            # absolute dir this script is in
            script_dir = os.path.dirname(__file__)

        abs_file_path = os.path.abspath(
            os.path.join(script_dir, rel_file_path))

        if not os.path.exists(abs_file_path):
            self.log.error(abs_file_path + " does not exist.")
            if quit_on_error is True:
                raise RuntimeError("Imported file not found. Quit.")

        return abs_file_path