This is an Excel97/2000 method. It is required to perform more complicated merging than the normal setAlign('merge'). It merges the area given by its arguments.
Parameter
integer $first_row -
First row of the area to merge
integer $first_col -
First column of the area to merge
integer $last_row -
Last row of the area to merge
integer $last_col -
Last column of the area to merge
