v0.4

Change the default internal serializer of pygear to JSON instead of pickle. This is to avoid issues arising from pickling and unpickling in potentially disparate python environments, which could lead to strange behaviour, as well as security issues relating to unpickling potentially malicious data.

The serializer can still be changed at runtime if desired using the set_serializer methods.
this should be called 'serializer' or something since it's not always cPickle.