JSONField can now accept an initial dictionary or list value (rather

than just a JSON-encoded string) when creating an instance of a model.

Previously, callers had to create the model and then set any

JSONFields, but this meant that JSON data couldn't be set in

Model.objects.get_or_create() calls unless that data was first

JSON-encoded (which could be unnecessarily expensive).
Now, the field first checks if it's dealing with a dict or list. If

so, it clones it and sets it directly. Otherwise, it proceeds to handle

JSON-encoded strings or None values as it did before, and then falls

back to raising an error if the type wasn't expected.

Unit tests passed.
Used this in some code I'm writing that passes JSON-encodable data

during model instantiation.