Return the individual info in a dictionary for json.

def to_json(self):
        """
        Return the individual info in a dictionary for json.
        """
        self.logger.debug("Returning json info")
        individual_info = {
            'family_id': self.family,
            'id':self.individual_id, 
            'sex':str(self.sex), 
            'phenotype': str(self.phenotype), 
            'mother': self.mother, 
            'father': self.father,
            'extra_info': self.extra_info
        }
        return individual_info