* Adds `SerializationProperty` - This will generate the private variable for serialization. Also provides an option `useField` to specify your own. Example:
```cs
[SerializationProperty(0, useField: nameof(_resource)]
```
* Adds `BeforeSerialized` for entities to handle cleanup.
* Adds `Created` and `LastSerialized` fields to all entities. While this is a big bloat, this will be necessary for identifying dangling references to other invalid entities.
* Changes formula for determining a valid reference to be _not null, not deleted, and reference's created date must be at or before the entities last serialized date_.
* Adds versioning to idx file and serializes `Created` and `LastSerialized`.
* Fixes Save Stats and also disables it by default.
