overhaueld the API: Basically it's reverting the last API overhaul, so class...

overhaueld the API: Basically it's reverting the last API overhaul, so class extenders are instantiated again. That way we won't run into troubles with late static binding of PHP <5.3, can properly implement the interface in extenders and extenders can make use of per extendable object variables.
However to ease explicit invocation of specific extenders an extender() method has been added to the faces extendable.
Also a test case for easy benchmarking of faces has been added and extending single methods without an interface is possible with functions now.