Add JSONP timeout support

Currently reqwest is missing timeout support on JSONP calls, as JSONP has no timeout or http status code it is impossible to detect if a request is successful or not. To build an application on professional basis it is mandatory to have a timeout added.

I added 2 tests to verify timeout support on regular XHR requests and JSONP request. 

(there was a small error in the server node test script, the test would fail if multiple cookies where stored as it always returned the 1 index, fixed it by retrieving the specific "cookie" value)