added support for {or: ...} and now returning data as label if label
undefined.

Change-Id: Iaba929021438f0d24d404e914c04829add434440
code cleanup

Change-Id: I02e4329211a6a14388ec71d8cdc23801b22f7368
Fixed bugs in ColumnTreeNode and added caching.
Refactored PartitionDataTransform to use ColumnTreeNode.

Change-Id: Ia34404639206ee2a7d7868e99393b564ee9d5ea1