title: AFNetworking and auto-suggest
body: <p>I'm using AFNetworking for my iOs app.
  I need to implement a search-suggest like in many other apps or search bars on  websites.
  So basically launch GET requests but cancelling old ones as users tap new chars.
  How can I do that? I have an AFHTTPClient subclass and I'am using getPath.
  The best would be to have this requests be cancellable and "prioritized" to any other HTTP request on my singleton AFHTTPClient subclass.
  Thanks in advance.</p>