TAdvGridExcelIO XlsEndCol/XlsEndRow properties

Introduce XlsEndCol/XlsEndRow properties to control the end of the range of cells to be imported in TAdvStringGrid

While it makes sense to have XlsEndCol/XlsEndRow, you can control the range today by setting AdvGridExcelIO.AutoResizeGrid := false and then resizing the grid to the range you want to import.

This feature was implemented.