title: what is the ipython notebook "Terminals" menu option
body: <p>I am running ipython notebook on my OSX machine and/or my ubuntu 14.04 machine.  I am using ipython 3.0.0, and ipython (jupyter) notebooks.</p>
  
  <p>When I start an ipython notebook, under New there is a terminal option, but it's unavailable for me.
  I haven't been able to find any documentation on this feature, how to activate it or what it does.
  The <code>ipython notebook --help</code> command doesn't mention it and I haven't found anything in the <a href="http://ipython.org/ipython-doc/dev/index.html" rel="noreferrer">documentation</a> either.
  I haven't discovered the special keywords to search google for to get any information either.</p>
  
  <p>What does this feature do? How do I activate it? Is there any documentation on this available?</p>
  
  <p><img src="https://i.stack.imgur.com/crK8E.png" alt="enter image description here"></p>