Excel Workbook functions; added new ISExcelCellRange object

Added support for Excel Cell Ranges via the ISExcelCellRange object.

This provides a better alternative to passing around the first column and row and last column and row or Cell References (top/left and bottom/right) in the format "A1" etc.

For example, this is used in the new ISExcelWorksheet.Sort and updated GetUsedRangeInformation functions, see below for an example:

Dim CellRange As ISExcelCellRange

If Worksheet.GetUsedRangeInformation(CellRange) Then
  finBL.DebugWatch(CellRange)
Else
  ' Error
End If

The following functions have been obsoleted and newer alternative functions added that use ISExcelCellRange:

• ISExcelWorksheet
• GetNamedRangeInformation
• GetUsedRangeInformation
• SetPrintArea