[Bigbang-dev] Updating Notebooks to v4 (Juptyer)

The notebooks in the BigBang examples directory have been version 3 since the project started. In the most recent version of IPython, the notebooks have been updated to v4 to include (among other things?) the language-agnostic Jupyter branding. I'm going to update these notebooks in a commit soon, as per this issue: https://github.com/sbenthall/bigbang/issues/174 Please update your IPython packages in your Python environment so that you can use the new notebooks. Thanks, Seb