Test (de)serialization at more stages. Reveals another bug - [workflow,task].data is not being serialised out properly.
Serialize data dictionaries. Reveals py2-only unicode v non-unicode issues.
use unicode( over str( - doesn't break py2
Merge branch 'feature/fix_serializer' into develop
Serializer that doesn't use pickle
Override Joins, which had a hidden pickle.
First attempt at NetworkX serializer