Formats various date formats to dd.MM.

        Examples
        - January 15th      --> 15.01.
        - 15.01.2017        --> 15.01.
        - 15th of January   --> 15.01.
        - 15.1.             --> 15.01.

        Keyword arguments:
        dl_string -- a string to be formatted

        Returns:
        Date string in format dd.MM. or "None.None"

def format_date(self, dl_string):
        """Formats various date formats to dd.MM.

        Examples
        - January 15th      --> 15.01.
        - 15.01.2017        --> 15.01.
        - 15th of January   --> 15.01.
        - 15.1.             --> 15.01.

        Keyword arguments:
        dl_string -- a string to be formatted

        Returns:
        Date string in format dd.MM. or "None.None"
        """
        thedate = get_simple_date(dl_string)
        if thedate != "Failed" and thedate:
            return thedate

        day = get_day_of_month(dl_string)
        month = get_month(dl_string)

        return day + '.' + month + '.'