function checkComplete() {
                                    if (++i == scrapers.length) {
                                        // save state
                                        page.state = page.evaluate(function() {
                                            return _pjs.state;
                                        });
                                        // run completion callback
                                        complete(page);
                                    }
                                }
Scrape a single page.
@param {String} url          Url of page to scrape
@param {Function} scrapePage Function to scrape page with
@param {Function} complete   Callback function to run when complete
@private