a wrapper to print_config_value to print all configuration values
            Parameters
           ==========
           prefix: the character prefix to put before the printed config value
                   defaults to "- "

def print_config_values(self, prefix='- '):
        """a wrapper to print_config_value to print all configuration values
            Parameters
           ==========
           prefix: the character prefix to put before the printed config value
                   defaults to "- "
        """
        print('Configuration values from ' + self.config_dir)
        self.print_config_value(self.CONFIG_NAME_USER, prefix=prefix)
        self.print_config_value(self.CONFIG_NAME_PATH, prefix=prefix)
        self.print_config_value(self.CONFIG_NAME_PROXY, prefix=prefix)
        self.print_config_value(self.CONFIG_NAME_COMPETITION, prefix=prefix)