Prepares a request from a url, params, and optionally authentication.

def make_request(self, url, params, auth=None):
        """
        Prepares a request from a url, params, and optionally authentication.
        """
        req = urllib2.Request(url + urllib.urlencode(params))

        if auth:
            req.add_header('AUTHORIZATION', 'Basic ' + auth)

        return urllib2.urlopen(req)