Add testing support to the examples

The examples section of this repository demonstrates a few great ways to configure and integrate connected-react-router into a project. However, none of the three provided configurations use a testing framework in their source code.

I find writing integration tests for components using connected-react-router to be difficult. It would be great if someone could add a "testing" section to the docs, or add another example configuration to examples that would demonstrate how to write tests with connected-react-router.

This may or may not be a trivial task, though I hope I am not alone in wanting this clarification.