Major touchup

* Added docblocks
* Added namespace
* Improved composer configuration
* Streamlined the API (BC Breaks).
* Refactored code for more readability
* Added adapters. Guzzle as client is now interchangeable.
* Added request and response filters. Users can now modify the Symfony requests and responses to their liking.
@jenssegers Using the proxy in this case is wrong. If there is no request, then there is nothing to proxy imho.