CiviReport Membership Detail Report Includes First and Last Name

The membership report "Detail" and "Lapse" in CiviReport only show the concatenated "display name". This makes sorting the results alphabetically by last name very problematic.

While I realize that Organizations do not have First and Last names, Individuals do. As such, First and Last name should be available as optional fields in these reports.

Attached are patches for improve the reports.