Add UDC stats for numbers of IDs in use in store.
Updated Logback to 1.1.2
Merge pull request #2438 from benbc/2.1-more-udc-stats

Add UDC stats for numbers of IDs in use in store.
Fix unit test so it runs predictably
fix bug in batch-insertion, CalculateDenseNodesStep. No call to super to shut down the Executor
Merge pull request #2445 from jexp/batch-inserter-done

fix bug in batch-insertion, CalculateDenseNodesStep.
Typo
Cypher vs SQL chapter.