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Enhancements:
+ Import REASON_CODES from Django
+ Use Django's JsonResponse if available, or our own copy of it.
+ Unify all json handling functions into utils.JsonMixin
+ Add RPCView introspection
+ Use Django's vendored copy of 'six'
+ Add new runtests script
Bug Fixes:
+ Cope with blank content encoding values in RPC Views
+ Raise a 404 on invalid page_size value
+ Validate the data we got in RPC View is passable as \**kwargs
+ ISO_8859_1 isn't defined in older Django versions
+ Emulate django template lookups in digattr by ignoring callables flagged
'do_not_call_in_templates'