High memory usage

[Tsarcasm]

Since all entities are supposed to be immutable, we end up with a unique entity being created each time one needs to change. That's ok, and probably will stay the same.
There is an issue when you get an object from a DatabaseStore, since due to (perhaps bad) past decisions we create a copy each time DatabaseStore#get is called.
We probably don't need to create copies each time get is called, but this needs to be tested