gnosplit/v1 package

Package gnosplit shares a group's expenses, like Tricount: who paid what, who owes whom, and the fewest transfers that settle everything.

A group has members, each a name with or without a wallet. Members with a wallet linked are the group's editors: they record expenses, incomes and transfers, and get a gnotif notification when one concerns them. Members without one are just names: a friend with no wallet still has a balance.

Amounts are cents of the group's currency, a label such as "€" or "CHF": no coin moves here, a transfer records a payment made elsewhere. Every balance is kept up to date on each write, so reading a group never adds up its history.