v0.1.6

• Made model struct immutable and Clone-able so it can be re-used (issue #12) (thanks @kornelski!)
• Made Rectangle public (thanks @kornelski!).

v0.1.5

• Reduced use of unsafe (thanks @kornelski !).
• Performance improvements (thanks @kornelski !).

v0.1.4

• Made Rayon an optional dependency using a feature flag. It is enabled by default. Parallel processing can now be disabled by providing the --no-default-features flag at build time.