yui/yui3 — pull request #1976 by theogravity (2014-10-21 20:59:52+00:00)
Title: Fix model-sync-local corruption

1. Define a model with multiple attributes.
2. Create a model that uses the model-sync-local extension.
3. Set *more than one* model attributes
4. call `model.save()`.
5. The extension incorrectly saves to local storage (data shows as '[Object Object]').

This change fixes this by stringifying the key/value pairs in the `_update` method.