Introduce sorting parameters for BP_Group_Member_Query

[boonebgorges]

See #5106 for original enhancement request.

From aaclayton:

It would be really great to include sorting arguments in bp_groups_has_members(). I think that this function could accept “type” and “sort” arguments, where “type” could take values of either ‘user_id’ or ‘last_modified’, and “sort” would be either ‘ASC’ or ‘DESC’.

From an organizational perspective, a group member’s join date is (typically) a more informative sorting variable, and depending on the use case, either ascending OR descending could make more sense. Giving BuddyPress users the ability to tweak their loop sorting in the function would be great.

Let's try for this in BP 1.9.

[boonebgorges]

This was taken care of in the work leading up to #921.