Allow clearing of empty BGS tallies

[Greymagic27]

I have lots of entries under 'previous BGS tallies' which have lots of systems but no activity as they're deep in space without any stations.

It would be nice to have a button to delete these entries that have no activity in them

[aussig]

The 'Previous Tallies' list is limited to 20 game sessions. All older tallies are automatically moved to an archive folder inside your activitydata folder, so you can manually look at them if you wish, but they are not accessible from within EDMC.