Implement ISheet.Cells[] and ISheet.Rows[]

[tonyqus]

Implement #1448

Supported Syntax

Cell Range

var cellRanges = sheet.Cells["B1:D3"]; // cell range
var cellRanges = sheet.Cells["A1"]; //Single cell
sheet.Cells["A1:B2"].Value="Hello World";
sheet.Cells["A1:B2"].SetCellValue("Hello World");
sheet.Cells["A1:B2"].Formula = "A1+B1"
sheet.Cells["A1:B2"].SetCellComment(comment)
sheet.Cells["A1:B2"].Where(c=>c.RowIndex==2) (LINQ Support)
sheet.Cells["A1:B2"].Texts //returns text value array

Row Range

sheet.Rows[1, 5].Height=500
sheet.Rows[1, 5].Group()
sheet.Rows[1, 5].Ungroup()

Extra Fixes

implement XSSFSheet.SetActiveCellRange
implement XSSFRow.SetRowStyle
implement SXSSFRow.GetEnumerator