[BUG] Orders|Trustlines|Balances: Allow ledger hash query parameter (RLJS-137)

I don't like this assumption of ripple-lib's internals, it will break if we change ripple-lib. I don't see a way that's currently "better", as copying the logic from ripple-lib is duplicating code that's unnecessary and I do think ripple-lib should be the authority on how to deal with ledger heuristics. We could expose a method in ripple-lib that gives you a clean api to do so, but not sure where that would properly fit. This is fine for now, but I would write unit test around this specific function.