Alter Reports updated: now with subheadings and footer

Important update for Alter Reports:

New Subheadings row with ability to span above few heading columns.

Footer row: each column can have custom footer value or auto-calculated values (minimum, maximum, average and sum).

XLS reports can have footer values either pre-calculated or have formulas (built-in AVERAGE(), SUM(), MIN(), MAX() or you can use own formula with replaceable tags of column data rows coordinates).