STANBOL-969 SemanticIndex for enhancements is implemented. * EnhancementSemanticIndex indexes all enhancements of the submitted ContentItems. These documents can be queried over sparql endpoint of the project. * Default configuration is added for the creation of the default EnhancementSemanticIndex
stanbol/branches/contenthub-two-layered-structure/contenthub/defaults/src/main/resources/config/org.apache.stanbol.contenthub.index.clerezza.EnhancementSemanticIndex-default.config