Media Explorer: Retain sort-settings in 'Detail' view

When the Media Explorer's view is in Details mode, which includes sortable columns, the last sort-by and sort-order settings should be maintained from dir to dir, and also after the explorer has been closed and reopened.

This should be at least on a global basis, if not on a per-dir basis.

Having to resort them every time is a pain, and just sooo Cakewalk!