quicksafe: moving to 'proxy' approach

instead of letting the library hold the layout specific part,
the layout specific object shall hold the library, becoming a 'proxy' so to say.

develoeprs can use the library object to do native xpath queries _but_
they can setup proxy objects with their 'own' language, respecting their
own xml markup for instance. within the proxy object, the specialized/localized
query string has to be transformed into a valid xpath query.
let's see ..