HOTFIX: Use '?.' operator to avoid NullpointerException
Refactoring: Rename facet constants to distinguish between alalysed and
not analysed facets
Facet refactoring
Move facet method back from isSavedSearchFacet to isSearchFacet
Fix variable name
Fix Javadoc
Merge branch 'develop' of https://github.com/Deutsche-Digitale-Bibliothek/ddb-common.git into develop
Merge branch 'APD-503-BOZ' into develop