Remove DOM factories for React v16

[jfsiii]

React 15 prints this warning:

Warning: Accessing factories like React.DOM.div has been deprecated and will be removed in v16.0+. Use the react-dom-factories package instead. Version 1.0 provides a drop-in replacement. For more info, see https://fb.me/react-dom-factories

So, code like

React.DOM.input(...)

needs to become something like

import DOM from 'react-dom-factories'
DOM.input(...)

or, perhaps

import { input } from 'react-dom-factories'
input(...)

[stephenlacy]

fe479ead23b3037df5d01deece7cb6da17ee98f5 🎉