Fixing issue where data flattening in request was calling the wrong method. This was causing POST's tp fail.

src/JonnyW/PhantomJs/Message/Request.php

@@ -203,7 +203,7 @@ class Request implements RequestInterface
 
 			if(is_array($value)) {
 
-				$flat += $this->flattenArray($value, $ref, '[%s]');
+				$flat += $this->flattenData($value, $ref, '[%s]');
 				continue;
 			}