Fix account_lines, account_offers and book_offers result (RIPD-682):
The RPC account_lines and account_offers commands now respond with
the correct ledger info.
account_offers, account_lines and book_offers allow admins unlimited
size on the limit param.
Specifying a negative value on limit will be clamped to the minimum
value allowed.
Incorrect types for limit will be correctly reported in the result.