Restart behaviour Jupyter 4.1

[cgravill]

There is new functionality around restarting kernels in Jupyter 4.1 (http://blog.jupyter.org/2016/01/08/notebook-4-1-release/#restartkernelandrunall). This isn't working cleanly with IfSharp.

1. Start a new kernel
2. Write some F# code
3. Trigger a restart
4. (nothing apparently happens… wait a few seconds)
5. Jupyter detects dead kernel and offers to restart
6. Actually restarts
7. Write some more F# code

This isn't a fatal problem but it's very irritating in practice.

[cgravill]

This has been resolved by #64