[TASK] Add balance_change array to transaction response, computed from metadata

Why does it need to be JSON-stringified?

>It looks confusing to me. If I'm a newbie ripple-lib open source developer, I would think "is that a bug? what happened to the currency for that first one?"

Yeah, it's unfortunate that amounts in Ripple have this discrepancy, but it would be more confusing to developers if XRP is represented as non-drops in only one place (as you suggest). ripple-lib's purpose isn't to radically simplify--this is REST's job. ripple-lib uses the same amount formats as rippled.

PS if that is the expected output, I'd disagree with that too. Should be more like

`
{
"account": "rAsdf",
"balance_change": AmountObject
}
`