Closed Issue: Create new methods [8287]

Create the following methods:
 
range.UniqueRows()
range.UniqueColumns()
column.UniqueCells()
row.UniqueCells()
range.DeleteDuplicateRows()
range.DeleteDuplicateColumns()
row.DeleteDuplicateCells()
column.DeleteDuplicateCells()
Comments: Please try the latest version of ClosedXML (v0.87.1 at this stage). If you still experience the issue, log it on the new GitHub page.