Ignore money_format when using a non-decimal currency.

**Problem**
Many gateways expect the purchase amount to be passed in the minor currency unit. However, many gateways also expect the Yen (and other non-decimal currencies) to be passed in the major currency unit. Activemerchant would not account for this and would wrongly send too large of a value when using these currencies.

**Changes**
The `localized_amount` method now ignores the `money_format` variable for non-fractional currencies.
IE 100 sens will become "1" yen even if `money_format = :cents`

This also changes both eway_rapid and secure_pay_au to make use of the `localized_amount` method instead of the standard `amount` method since.

@odorcicd @girasquid 
/cc @jduff