Grouping sorting options

[mstijak]

Currently, we cannot sort data after grouping. Groups are returned sorted by string based group keys. In case of numerical values this is not optimal because we get results like '1', '10', '2' and it's not possible to get data in reverse order. Therefore, the Grouper class should be revisited.

[nebojsa-peric]

Any idea when you will be working on this? :) We have a use case where we would like to keep the records in the order they were in before the grouping. So it would be nice to either skip sorting, or define some custom sort priority property to achieve this.