furrow v0.3.3

What's Changed

• test: set the mode the portable exchange test asserts by @santoshkumarradha in #18
• perf: O(1) pack checkpoint validation; fast read-only opens by @santoshkumarradha in #17
• release: 0.3.3 by @santoshkumarradha in #19

Full Changelog: v0.3.2...v0.3.3