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* Removed Django 1.7 and Python 3.2 support
* Added system check to disallow related_name='+' on ParentalKey
* Added support for TAGGIT_CASE_INSENSITIVE on ClusterTaggableManager
* Field values for serialization are now fetched via pre_save (which, in particular, ensures that file fields are committed to storage)
* Fix: System checks now correctly report a model name that cannot be resolved to a model
* Fix: prefetch_related on a ClusterTaggableManager no longer fails (but doesn't prefetch either)
* Fix: Adding invalid types as tags now correctly reports a ValueError