[#79] Entities: Remove EF proxies

Elwig/Windows/PaymentVariantsWindow.xaml.cs

@@ -48,7 +48,6 @@ namespace Elwig.Windows {
             ControlUtils.RenewItemsSource(PaymentVariantList, await ctx.PaymentVariants
                 .Where(v => v.Year == Year)
                 .OrderBy(v => v.AvNr)
-                .Include(v => v.Season.Currency)
                 .ToListAsync());
             if (PaymentVariantList.SelectedItem == null && PaymentVariantList.Items.Count > 0) {
                 PaymentVariantList.SelectedIndex = PaymentVariantList.Items.Count - 1;