Add PromiseKit to SDK dependency in Podspec file.
Fix bug in Date Transform that called method on NSNumber that did not exist.
Fix SLUser keyForAttribute such that deserialization properly extracts out the firstName, lastName, and jobTitle of the payload.
See #7. Unsuccessful authentication now rejects correctly with an NSError instead of NSException.
See #7, #8. keyForAttribute function now automatically underscores the attribute key.
See #4, #5, #6. Upgrade Asset, Attribute, AttributeCollection models.