Add grouping options for task Print PDF Letter for Contribution

When doing search contribution -> task Print PDF Letter for Contribution, it would be great to group by criterias as recurring contribution or contact to allow to print only one pdf even if there are several contribution.
Also, we need to add some of the most used "aggregation" token like total sums, first receive date, last receive date.
Third, we need an easy way to print a list or table of aggregated contribution in one letter.