* Moved implementation of getting and updating a DOM wrapper to ve.ce.BranchNode
* Updated ve.ce.BranchNode tests
* Renamed ve.NodeFactory.createNode to ve.NodeFactory.create
* Added ve.NodeFactory.lookup which gets the constructor of a type
* Added attribute pass-through to ve.dm.BranchNodeStub
Change-Id: I8f5b7d3d3ae616cc5f39828b24b655163d782ae5
* Added support for asking if a given node type can have children or grandchildren and what types of nodes can be it's parent or child
* Removed canHaveChildren methods from leaf and branch nodes and converted use of them to depend on factory to read static rules from constructor lookup by type
Change-Id: I9769f95647066576416bacb791c4b68dd0285b35