Allow use of decimals even for whole currencies #120
Description
I am often paid in Japanese Yen (JPY) but my rate isn't always set to a whole number, despite the fact Japanese yen only uses whole numbers.
For example, I've had a rate of 4.5 yen, which when multiplied many thousands of times added up to a whole number.
If I try to set a decimal when using JPY, it displays everything correctly in the editor UI, but when I hit save it always rounds up to the next whole number, meaning I can't export my invoice to a PDF with the correct values.
I would very much appreciate if there was an option to set any decimal value we want in any currency, or at least a couple decimal places. Otherwise it's impossible for me to use this software for invoicing Japanese clients.