ChromeOptions: setExperimentalOptions, addArguments

Start Chrome with arguments.

Example,
```
$options = new ChromeOptions();
$options->addArguments(array('--window-size=300,900'));
$caps = DesiredCapabilities::chrome();
$caps->setCapability(ChromeOptions::CAPABILITY, $options);
$driver = RemoteWebDriver::create($url, $caps);
```