bump sesame and slf4j versions
remove aduna repository, as sesame-2.7 is going to be deployed to sonatype and maven central
add sonatype snapshot repository to fetch sesame-2.7-SNAPSHOT artifacts
remove aduna-commons packages that are not used independent of sesame
bump to sesame-2.7.0-beta2-SNAPSHOT
add new ValueFactory methods to Any23ValueFactoryWrapper
modify N3 mimetype to match current W3C team submission