title: Ipython broke: doesn't start, says missing 'pathlib2' distribution
body: <p>When i execute ipython in terminal i see following error</p>
  
  <pre><code>aman@ebex-MacBookPro:~/ipython_work$ ipython                                                                                       
  Traceback (most recent call last):                                                                                                 
    File "/usr/local/bin/ipython", line 5, in &lt;module&gt;                                                                               
      from pkg_resources import load_entry_point                                                                                     
    File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 3141, in &lt;module&gt;                                  
      @_call_aside                                                                                                                   
    File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 3127, in _call_aside                               
      f(*args, **kwargs)                                                                                                             
    File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 3154, in _initialize_master_working_set            
      working_set = WorkingSet._build_master()                                                                                       
    File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 640, in _build_master                              
      ws.require(__requires__)                                                                                                       
    File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 941, in require                                    
      needed = self.resolve(parse_requirements(requirements))                                                                        
    File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 828, in resolve                                    
      raise DistributionNotFound(req, requirers)                                                                                     
  pkg_resources.DistributionNotFound: The 'pathlib2' distribution was not found and is required by ipython   
  </code></pre>
  
  <p>Just before that i followed </p>
  
  <pre><code> $ git clone --recursive https://github.com/ipython/ipython.git
   $ cd ipython
   $ pip install -e ".[notebook]"
  </code></pre>
  
  <p>From the link [How to autosave ipython notebook]</p>
  
  <pre><code>http://stackoverflow.com/questions/21517296/how-to-autosave-ipython-notebook
  </code></pre>
  
  <p>I tried to uninstall and install using apt-get but its still not working and throwing missing distribution error.</p>
  
  <p>I installed pathlib2 though</p>
  
  <pre><code>sudo pip install pathlib2
  </code></pre>
  
  <p>But again while accessing ipython 
  I see another error</p>
  
  <pre><code>pkg_resources.DistributionNotFound: The 'backports.shutil_get_terminal_size' distribution was not found and is required by ipython
  </code></pre>