RFC: ls size and cumulative size

[alanshaw]

The current rationale wants ls size to be the TOTAL size of the node and it's children including any protobuf wrappers. There is existing a cumulativeSize field and I think that we should use this field to convey that information and use size to be the size of the data contained in the node and any of it's children i.e. excluding protobuf wrappers.