Double quotes are not handled properly

[itagagaki]

v1.3.4
A comma inside double quotation marks splits a string into two columns.
Any characters within double quotation marks should not be treated as delimiters.

[itagagaki]

Ah, okay. This area needs improvement.

ExcelMerge/ExcelMerge/CsvReader.cs

Lines 18 to 19 in 5ac3519

	foreach (var c in sr.ReadLine().Split(','))
	cells.Add(new ExcelCell(c, columnIndex, rowIndex));