Polishing in annotations of PagedResources.
#72 - Improved mapping discovery in AnnotationMappingDiscoverer.

AnnotationMappingDiscoverer now returns a polished mapping in case the type mapping consists of a plain slash only.
#73 - ControllerLinkBuilder does not reject unmapped types anymore.

ControllerLinkBuilder now simply assumes an empty mapping if no type-level mapping can be found.