Remember folder for MCDF Import and Export (#48)

* remember last MCDF directory

* name mcdf export from description

MareSynchronos/MareConfiguration/Configurations/MareConfig.cs

@@ -36,4 +36,5 @@ public class MareConfig : IMareConfiguration
     public int TransferBarsWidth { get; set; } = 250;
     public int Version { get; set; } = 1;
     public NotificationLocation WarningNotification { get; set; } = NotificationLocation.Both;
+    public string ExportFolder { get; set; } = string.Empty;
 }