react-perf-devtool

Some minor changes -

• Updated to use ES6 imports
• Updated syntax for registering the observer.

Earlier

const registerObserver = require('react-perf-devtool')

registerObserver()

Current

const { registerObserver } = require('react-perf-devtool')

registerObserver()

• Updated documentation
• Fixed #19 in create-react-app
• Fixed broken tests