Remove duplicate category.

Fix changing main currency.
Fix currency conversion.
Pre-Select main currency when adding a new subscription.

includes/list_subscriptions.php

@@ -50,7 +50,7 @@
             return $price;
         } else {
             $fromRate = $exchangeRate['rate'];
-            return number_format($price * $fromRate, 2);
+            return number_format($price / $fromRate, 2);
         }
     }