Upgrade open() method to accept unlimited params

In extension of the setScript() method, I needed to be able to send
arguments directly to the command line.

The changes to the open() method will allow the user to send parameters
to the command line, to be used in conjunction with arguments the
selected script requires.

example usage below:

/**  @var $client JonnyW\PhantomJs\Client */
$client = App::make("PhantomClient");

$client->setScript("https://raw.github.com/ariya/phantomjs/master/examples/direction.js");

/**  @var $request JonnyW\PhantomJs\Message\Request */
$request = $client->getMessageFactory()->createRequest('GET',
'doesnotmatter.com');
$request->addHeader('User-Agent', 'Mozilla/5.0 (Macintosh; Intel Mac OS
X) AppleWebKit/534.34 (KHTML, like Gecko) PhantomJS/1.9.2
Safari/534.34');

/**  @var $response JonnyW\PhantomJs\Message\Response */
$response = $client->getMessageFactory()->createResponse();

// Send the request
$client->open($request, $response, "london", "paris");

echo $response->getCommandLine();

Further, I've made adjustments to the response class to handle calls
back from the command line.