Negative Rollover option -- incorrect budget amount

[ScottAbbey]

When using the negative rollover option, it carries over the overspent amount in the available-to-budget calculation, but it should ignore that amount instead.

Example with current code:

January

Name	Amount
Funds for month	100
Overspent in prev month
Budgeted for month	-100
To be budgeted for month
Budgeted in the future

Category	Budgeted	Spent	Available
Food	50	-55	-5
Rent	50	-50

February

Name	Amount
Funds for month	100
Overspent in prev month	-5
Budgeted for month	-100
To be budgeted for month	-5
Budgeted in the future

Category	Budgeted	Spent	Available
Food	50	-50	-5
Rent	50	-50

Notice that the total amount available for the two months was 200, and 200 was budgeted, but the system says you have over-budgeted by 5.

Instead, it should look like this when negative rollover is used:

February

Name	Amount
Funds for month	100
Overspent in prev month
Budgeted for month	-100
To be budgeted for month
Budgeted in the future

Category	Budgeted	Spent	Available
Food	50	-50	-5
Rent	50	-50

Since the overspent amount from the previous month is left on the accounts as a negative available amount, we can't deduct that from the available amount to budget.