Model Caching

[ztnel]

I think it makes more sense to enforce all state models to cache all the time. The reason is because all definitions that are state models and have those caching functions defined should use them always instead of requiring developers to include cache=True for each state commit they want to cache. That requires remembering to cache that specific model type every instance its changed. Instead the decision whether model changes should be cached should be decided when that model is defined so the system caches it all the time. The disadvantage of making caching granular at the model level means that fast updating parts of a model constrain the ability for that whole model to be cached efficiently since it involves disk writes.