Make the bank wire more useful in a multiple currencies shop

With the default bank wire module, if the shop has multiple currencies, it is proposed to the customer only if the merchant accepts payments in all currency. If the merchant accepts payments just in its own currency, the bank wire will not be proposed to the customer that visit the shop with a different currency. That's wrong!

PayPal don't works in this way, the shop can have multiple currencies and it is proposed to everyone but the merchant can receive in its own only.

This mod permits to propose the bank wire in a multiple currencies shop, but it add a step that permit to the merchant to receive payment in its own only.
This is just a "front-end" mod, it needs some work to bring it totally configurable in the BO by adding variables, checkboxes, etc. All this is too much for me, I'm not a developer, unfortunately...

In the present mod I made changes directly in the code (so they are not OK for everyone):
- I use "Euros" as default currency (it should be choose in BO among all installed currencies of the shop, if any)
- It works with currencies ID (in this mod: euros=1, dollar=2, pound=3. Everything should follow the installed currencies, if any)

I added some message to help customer and the merchant in the payment process and I have made some changes to make the return page of the bank wire payment trying to have it more complete and readable. I added an important comment about receiving the full amount of money (bank charges should be charged to the customer). Everything following the default theme style and colour.

Sorry if I made something wrong, I'm a super-newbie, in the PS forge bugfix website I was advised to join here to propose my fixing and chages.