message: react preset and hot reload plugin
diff: {
  "presets": [
  - ["env", {
  + [
  + "env", {
  "targets": {
  "browsers": ["last 2 versions", "safari >= 7"]
  },
  "include": ["transform-es2015-arrow-functions", "es6.map"]
  - }]
  + }
  + ],
  + "react"
  ],
  "plugins": [
  - ["babel-plugin-transform-runtime", {
  + ["react-hot-loader/babel",
  + "babel-plugin-transform-runtime", {
  "helpers": false,
  "polyfill": false,
  "regenerator": true
  