Logs out and quits the current web driver/selenium session.

def close(self):
        """Logs out and quits the current web driver/selenium session."""
        if not self.driver:
            return

        try:
            self.driver.implicitly_wait(1)
            self.driver.find_element_by_id('link-logout').click()
        except NoSuchElementException:
            pass

        self.driver.quit()
        self.driver = None