Remove explicit version from version_overview.rq
Replace variable version with graphName
Move metadata about deltas to version graph
Adapt added_concepts.rq, fix errors in loading
Add ng definition for version graph; introduce hasVersionHistory/isVersionHistoryOf
Link vhr with xhv:prev
Update current_version.rq
Update version_overview.rq
Add version_graph.rq
Adapted added_concpets*.rq
Improve style
Adapt deprecated/deleted_concepts.rq
Adapt concept_deltas.rq
Adapt concept_history.rq
Fix sparql endpoint
Add sparql service description in the default graph
Minor fixes
Additional example for concept_deltas.rq