2.0.0

Complete codebase rewrite. In short:

• Pure functional approach. No object-oriented code.
• Use { x: 1, y: 2 } instead of [ 1, 2 ] to denote a point.
• Use { a: 1, b: 2, x: 3, y: 4 } instead of Transform to denote a transform.
• Rearrange code and API into submodules
• New analysis tools: mse, rss
• Switched from ES5 to ES6: const and let instead of var etc
• Switched testing framework from mocha to tape
• High quality generated API documentation