Option to negate amount during conversion

Issue summary: 

When converting credit card transactions CSV files I need to negate the amount when it is converted into a QIF file.
The CSV files show purchases as +$ amounts and payments as -$ amounts.
The program that I import the QIF files into requires purchases to be -$ amounts and payments to be +$ amounts.


Issue changes: 
Project: CSV Converter »
Status: Active » Closed (works as designed)

You can map the amounts using Debit or Credit.
To invert the signal, just swap the columns.