Additional currencies mod

A little mod that adds the US Dollar (to start) into the game (at a value of €1.00 = $1.25, as of this post's current edit the actual EUR to USD exchange rate is €1 = $1.26), USD on the Currency dropdown menu.

Also updates the Czech Koruna (CZK) and Hungarian Florint (HUF) to values closer to the current exchange rates (at 27.50 Kč = 310 Ft = €1, changed from 25.00 Kč = 293 Ft = €1, current actual is 27.49 Kč = 310.87 Ft = €1)

The British Pound Sterling (GBP), Swiss Franc (CHF) and Polish Złoty (PLN) are unchanged as they are within 0.05 / 5% of the game default. (Game default/Current are 0.80/0.78, 1.20/1.21 and 4.20/4.18 for the GBP, CHF and PLN respectively)

I will try to update this (with current exchange rates within 0.05 of the currency being converted to or to the nearest 5%, whichever is the greater) at the beginning of every month and will also add new currencies (if requested) when I make said updates.