Small classes shouldn't be version

[nilsdeppe]

We are currently versioning a lot of tiny classes (inconsistently) all to version the Domain we write into the HDF5 files. One example is Direction, where the fact that we version it actually doubles the size of the serialized object. Another is FixedHashMap. This also greatly restricts our ability to change the code. Given that we don't have a stable release where we can do the science we want, this extreme versioning of everything actually hinders development. For example, while making changes to Direction I spent more time dealing with versioning than with actually changing the code. The versioning should be purely handled at the Domain level since that's the class we actually care about. This is what I've seen in industry and is actually scalable, whereas our current approach I think is not.