type safe InstanceBuilder.findPath implementation

The dynamic implementation lead to problems when 'class' was provided as
name, because this was interpreted as getClass call on the accessor
itself.

Change-Id: Ifcadc3cfb03ba836202773c5c6ff6752a3d27928
Reviewed-on: http://gerrit.esdi-community.eu/3165
Tested-by: Jenkins <sitemple@igd.fraunhofer.de>
Reviewed-by: Simon Templer <simon.templer@igd.fraunhofer.de>