title: Ipython notebook caching issue
body: <p>Within ipython notebook I call a function imported from my own module and run some code.  I have noticed that if I change the code in the function (outside of notebook) and execute the notebook the old version of the function runs.<br>
  Either ipython notebook or firefox seems to be caching the module which I can clear with ctrl-F5, when I remember.  Is there an ipython notebook function call to ensure I am running the newest code?</p>