[paymentrequest] No mention of non-decimal currencies (#40)

The [CurrencyAmount](http://wicg.github.io/paymentrequest/specs/paymentrequest.html#currencyamount) section doesn't mention [non-decimal currencies](https://en.wikipedia.org/wiki/Non-decimal_currency).

The correct behavior is probably to not use the sub-unit for Mauritania & Madagascar, and consider the Sovereign Military Order of Malta unsupported.

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Reply to this email directly or view it on GitHub:
https://github.com/WICG/paymentrequest/issues/40