Change recommendation for Alamofire integration

Issues with recommending Alamofire-SwiftyJSON:
-  Not updated for Xcode 6.1.
-  No longer necessary as a shim to integrate Alamofire and SwiftyJSON.
- Adds another dependency that needs to be manually included and managed.

I feel that recommending a third, separate dependency is confusing and unnecessary to new users.  It's only one line to have SwiftyJSON wrap the JSON returned by Alamofire.