Add currency converter

[alensiljak]

Option 1 - converter form Add an independent form for quick currency conversion that utilizes the latest downloaded rates. Add an input box for an amount and below that display used currencies with the values.

Option 2 - rate for transfers Add an option in multi-currency transfer to convert to/from an amount. Example: enter amount, click a button to convert that amount into the other (to/from) field. A button for rate update would also be useful. See Financisto transfers. Show a separate Rate field with operation buttons for: using the today's rate, entering today's rate, downloading today's rate, using the calculated rate from the entered amounts. This is #227

Option 3 - entering amounts in different currency Next to the amount entry field, add a button that opens the currency converter. Select the source currency and enter a value. The destination currency is the currency of the original amount field. Accepting the value, uses the calculated value as the number for the amount field. This is also possible to implement in such a way that the globe button opens just the currency selector. After selecting the currency, show a confirmation dialogue, explaining that the entered amount will be converted from the selected currency into the account currency and show the calculated amount.