Migrate to babel-preset-env and use babel-register in tests

v1.0.1

Reinstating skip_cleanup to preserve node_modules dir :(

1.0.0

• Avoid setState for rafId and isActive (previous commit)
• React 16 support
• Upgrade dev dependencies (Enzyme, React DOM etc.)
• Use Node.js 8 and npm 5 for local dev and CI

`startAnimation` method

Implement a startAnimation method (this.props.startAnimation) to restart the rAF loop after endAnimation has been called.