Feature request: Split with adjustments

[rafaeldamasceno]

In Splitwise there's a mode that splits an expense evenly with adjustments, i.e. the total amount minus the adjustments you insert for each person is divided evenly between the selected persons.

This is useful if you make a big purchase to split evenly but someone bought something only for themselves.

Say there is a 18€ expense to split evenly between Alice, Bob and Charlie, but Alice has a 1€ item for herself and Charlie has a 2€ item for himself.

The split would be as follows:

Person	Adjustment	Split	Total
Alice	1€	5€	6€
Bob	0€	5€	5€
Charlie	2€	5€	7€
Subtotal	3€	15€	18€