* The logic in the server and javascript frontend is there for
a basic JSON notebook format with a .ipynb extension.
* To save a new notebook: "%notebook save filename.ipynb"
* To save a notebook that is already saved: "%notebook save"
* To load a notebook from the cwd: "notebook load filename.ipynb"
Previously, each client (browser window) would open its own set
of ZMQ sockets to a kernel. Now one master set of connections
to the kernel is created and all clients share those connections.
In some ways, this simplifies the URL design.
I have also made kernel_ids server-side created.
Brian Granger