STANBOL-1031: The Jena TDB LDpath RDFBackend implementation now correctly handles literals with emtpy language; STANBOL-1016: implemented TripleFilter for the Jena TDB indexing source

git-svn-id: https://svn.apache.org/repos/asf/stanbol/trunk@1467865 13f79535-47bb-0310-9956-ffa450edef68