Quickfix backend
Added MarkerResolutionGenerator/MarkerResolution/XQueryResolver: These modules are used in the worker to compute quickfixes for given markers
Added simple quickfix applying: A quickfix contains the content of the editor if it would be applied - applying the quickfix is then done by replacing the editors content with quickfix.appliedContent. Issued by mouseclick/tab/enter on current quickfix in the quickfix-list.