4.2.4
- fixed ArangoDatabase.transaction(): ignore null result
- added properties validation arangodb.host
- added ArangoCollection.ensureIndex()
- made ArangoCollection.createIndex() deprecated
- let ArangoCursor implement Iterable
- fixed issue #145: ArangoCollection.updateDocument()
- fixed issue #145: ArangoVertexCollection.updateVertex()
- fixed issue #145: ArangoEdgeCollection.updateEdge()