foursquare.go
func (c *Client) RawRequest(url string) (*Response, *http.Response, error) {
	response := new(Response)
	resp, err := c.sling.New().Get(url).Receive(response, response)
	return response, resp, relevantError(err, *response)
}
func (c *Client) RawRequest(url string) (*Response, *http.Response, error) {
	response := new(Response)
	resp, err := c.sling.New().Get(url).Receive(response, response)
	return response, resp, relevantError(err, *response)
}
// RawRequest allows you to make any request you want. This will automatically add
// the client/user tokens. Gives back exactly the response from foursquare.