Reworked bbox optimisation in non-breaking fashion.

[rowanwins]

Hi @mfogel

I've had a go at reworking the optimisation in #24 so it's not as massive a change, basically no breaking changes are introduced.

I also had a go at adding some tests although I've got to confess I'm still finding jest a little tricky to navigate so it's not as tested as I'd like. Ideally it would be great to add a test if the break statement had been hit.

Let me know if you have any q's

Cheers

[coveralls]

Pull Request Test Coverage Report for Build 223

• 19 of 19 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.2%) to 97.922%

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Totals
Change from base Build 222:	0.2%
Covered Lines:	664
Relevant Lines:	670

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 223

• 19 of 19 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.2%) to 97.922%

---

Totals
Change from base Build 222:	0.2%
Covered Lines:	664
Relevant Lines:	670

---

💛 - Coveralls

[mfogel]

Bumping this to v0.12 as I would like to make v0.11 a bug-fix focused release.

[mfogel]

Haven't forgotten about this PR. I'm trying to investigate and fix as many of the bugs I know about before making other changes. Appreciate your patience!