Quick fix for IllegalArgumentException

Apparently, some dialogs first add the transactions only to set the
currency afterwards. The initial quick fix is to remove this safeguard
for now.

name.abuchen.portfolio/src/name/abuchen/portfolio/model/Account.java

@@ -94,9 +94,6 @@ public List<AccountTransaction> getTransactions()
     @Override
     public void addTransaction(AccountTransaction transaction)
     {
-        if (!currencyCode.equals(transaction.getCurrencyCode()))
-            throw new IllegalArgumentException();
-
         this.transactions.add(transaction);
     }