Tidemark v0.1.0-beta.2

Fixed

• Restart after a crash (kill -9, power loss) no longer checks the whole metadata file before
  the server answers. Every metadata commit now records the file's allocation state, so a restart
  takes well under a second whatever the metadata size (the 4 GB file from the beta.1 soak:
  22.8 s → 0.3 s). The first restart after a crash of a beta.1 or older process still does the
  full check once.
• Memory under heavy load: the metadata cache was a fixed 1 GiB, so a busy server with a large
  store grew past 1 GiB. New [storage] meta_cache (bytes, TIDEMARK_STORAGE_META_CACHE);
  the default 0 picks an eighth of RAM or the container limit, between 64 MiB and 256 MiB, and
  the server logs the value. On the beta.1 soak data under heavy load: 1 277 → 379 MiB peak, with
  throughput within run-to-run noise. Rolling back to beta.1 is safe: it opens metadata written by this release.

Changed

• scripts/soak.sh memory budget is now 512 MiB (256 MiB cache plus working set).
• scripts/bench.sh and scripts/soak.sh also run on macOS (stock bash 3.2); OPERATIONS.md
  "Soak" has the steps.