Checkboxes break with browserSync

Similar to https://github.com/react-component/checkbox/issues/13

I suggest adding
```
browserSync.create().init(
{
ui: false,
ghostMode: false,
...config,
},
resolve
);
```
to `react-union-scripts/scripts/startDevServer.js`, because a consistently working application is IMO better than this feature (or make `ghostMode` opt-in via a config option).

Start with react-union-scripts/scripts/startDevServer.js and inspect how browserSync is initialized. Verify the proposed ghostMode behavior or the suggested opt-in configuration; done means checkboxes continue working in a development session without unwanted BrowserSync interactions.

Written by the indexing model from the issue text.