Added the ThucydidesWebDriverSupport.getProxiedDriver() method to make it easier to retrieve the underlying proxied web driver instance.

Thucydides creates a proxy webdriver, but sometimes you need to access the underlying WebDriver instance.  You can now to this without having to do any casts or complex expressions like this:

        ChromeDriver proxiedDriver = ThucydidesWebDriverSupport.getProxiedDriver();