Can not export multi-line columns

[suin]

Currently, the exporter can output only one line column.
If a column has two or more lines, the exporter breaks CSV format...

CsvFileObject needs to while ( !feof($fp) )

        $line = '';
        while ( feof($fp) === false ) {
            $line .= fgets($fp);
        }

[suin]

duplicated from #11