Adjust to become a standalone library.

* Cleaned up documentation
* Changed namespaces, cleaned up quite some code.
* Adjusted the tests to be more friendly to run on a dev machine and to work with php 5.3 too.

there we go. i was quite busy. i tried to keep the code cleanups separate from the file move around crazyness so that you can give feedback on this.

i remove all symfony specific things in here. the only thing that is left is the client to varnish and the architecture around it. do you see anything that i removed too much?

note that i created a hard dependency on guzzle, as it makes no sense to use this library without it. that means that the FOSHttpCacheBundle should not require this lib - it will only be needed if you want the cache invalidation part but not for the cache rules part. or we say forget it, people just get guzzle into their project regardless if they need it, to keep it simpler.