Fix: createHashHistory import syntax (FormidableLabs#662)

This change fixes the following warning raised by ``history`` in the browsers :
```shell
Warning: Please use `require("history").createHashHistory` instead of `require("history/createHashHistory")`. Support for the latter will be removed in the next major release.
```

Author: jpbourgeon

src/utils/controller.js

@@ -1,13 +1,13 @@
 import React, { Component } from 'react';
-import createHistory from 'history/createHashHistory';
+import { createHashHistory } from 'history';
 import PropTypes from 'prop-types';
 import { updateRoute } from '../actions';
 import { countSlides } from './slides';
 
 import theme from '../themes/default';
 import Context from './context';
 
-const history = createHistory();
+const history = createHashHistory();
 
 export default class Controller extends Component {
   static propTypes = {