reference comparison:
https://github.com/Tuinity/Moonrise/compare/6a2c6d27df11d417c1fefa749109d8e87599e8c2...f22335f0b65e205831c74a7b4b8f4d93fff54fd5
todo:
- need to compare the diffs
- in ChunkEntitySlices, implement modifySavedEntities() by copying from old