Adding support for new currencies

[jacstn]

1. Objective

This PR adds support of all currencies offered currently by Omise.

2. Description of change

This PR adds new currencies to be considered in the amount formatting function.

3. Quality assurance

• Platform version: Magento CE 2.1.5.
• Omise plugin version: Omise-Magento 2.1.
• PHP version: 7.0.16.

✏️ Details:

1. Change the currency of Magento 2 store to any new currency offered by Omise (ie. DKK Danish Korona).
2. Make a successful order payment.
3. Verify if the amount of order is the same in Magento history and Omise Dashboard

4. Impact of the change

N/A

5. Priority of change

Normal

6. Additional Notes

N/A