v0.1.1

Fixed

• Parser reported Overflow for text carrying more significant digits than a
  u128 holds, even for values well inside the range: 1.0 written with 43
  decimal places, or a float printed as its exact expansion. Surplus digits now
  round the last one kept instead of failing the parse.

Added

• OrderBook::imbalance — (bid - ask) / (bid + ask) at the touch, in [-1, 1].
• OrderBook::range_imbalance(from, to) — the same over a half open band of
  levels. An empty or inverted band reads None, not zero.
• tests/fuzz.rs — proptest properties over Dec; make rs-fuzz sweeps wider.
• tests/fuzz_book.rs — capped-book invariants at 10, 50, 100 and 200 levels.
• benches/orderbook.rs — book operations by depth; make bench runs it.

Changed

• OrderBookSide drops its running total_amount. amount_mean and
  amount_std_dev sum on demand, trim becomes a truncate, and a non-finite
  amount can no longer poison a side for good.