Check that we're using these babel / webpack optimizations

[bbondy]

Check that we're using these babel / webpack optimizations:

"optimisation.react.constantElements",
"optimisation.react.inlineElements",

[hzoo]

In Babel 6, currently the react preset doesn't contain those plugins http://babeljs.io/docs/plugins/preset-react/.

Equivalents are:
http://babeljs.io/docs/plugins/transform-react-inline-elements/
http://babeljs.io/docs/plugins/transform-react-constant-elements/

// new .babelrc
{
  "presets": ["react", "es2015"],
  "plugins": [
    "transform-react-inline-elements",
    "transform-react-constant-elements"
  ]
}

[bbondy]

Able to do a PR?

[hzoo]

#280