copying out existing versioned-serializers code into shared/serializers/, adding into available serializers, doing proper imports and references.
cleanup from debug session that I missed in initial self-code-review.
Merge branch 'develop' of github.com:learningequality/ka-lite into save_the_django_serializers
cleaning cruft from django's serialize object
re-enabling fixture tests
OMG a merge conflict in a docstring. LOL
fixing undesired, debug-related cruft
Merge pull request #263 from bcipolli/save_the_django_serializers

Save the django serializers