Url refactoring

* When executed a block keeps its context and isn't instance evaled all the time (Shoes3 behaviour)
* We start with an instance_evaled block on app though (Shoes3 behaviour)
* no redirection on the block level, just on the method level e.g. when an URL does not know a shoes method it forwards the call to the app, as it keeps context that's cool
* for some reason this really made expert-tankpank-adjusted.rb fast and usable at least on my machine. Big JAY!
* meanwhile I also found out that the real performance killer for the menu is clear

I'm still up to write some specs especially for the things about the block context although I don't really know how yet. Probably also some refactoring let's see...

Please comment on the code etc. I hope that this is a lot more understandable now :-D