ICurrency == and != operators not returning expected result

[DrewBrasher]

I noticed this while stepping through the code in debug mode gathering details for issue #73. There are 2 places that use the ICurrency == and != operators and I think they should be using .Equals() instead because that method is overridden but the operators cannot be overridden in an interface.

Here are the 2 places the operators are used:

OrchardCore.Commerce/OrchardCore.Commerce/Drivers/PricePartDisplayDriver.cs

Line 62 in f6cc5e0

model.PriceCurrency = part.Price.Currency == Currency.UnspecifiedCurrency ? _moneyService.DefaultCurrency.CurrencyIsoCode : part.Price.Currency.CurrencyIsoCode;

OrchardCore.Commerce/OrchardCore.Commerce/Serialization/PrioritizedPriceConverter.cs

Line 37 in f6cc5e0

if (priority > int.MinValue && amount.Currency != Currency.UnspecifiedCurrency)

Here is a screenshot from debugging that shows the values:

and here is a screenshot after changing it to use the .Equals method: