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.
That implies that the Proxy object will have a half hearted state. The to be forwarded request is stored as property but the target url not? Sounds broken to me :(