Change string representation for a WebdriverActionRequest object; this makes it clearer in the shell that the request received is not a simple GET request but in fact a request for a Selenium webdriver in-page action.
A webdriver action has the ability to change the URL of the browser; yet when the download handler returns the response object it uses the request.url to set the response url and not the current url of the webdriver itself; this leads to the response being returned for parsing to Scrapy with the incorrect URL set against it. This commit changes that so that if an action changes the page URL, the response returned is set to the correct url.