title: Python modules not found in virtualenv
body: <p>I can't get modules to run in my virtual environment. Using pandas as an example:</p>
  
  <p>With the virtual env on I run <code>yolk -l</code> and get back (shortened version):</p>
  
  <pre><code>(basicpython)xxxx@LinuxBox:~/pythonprojects/basicpython$ yolk -l
  Python          - 2.7.3        - active development (/usr/lib/python2.7/lib-dynload)
  numpy           - 1.6.1        - active 
  pandas          - 0.7.0        - active development (/usr/lib/pymodules/python2.7)
  </code></pre>
  
  <p>So it is there. But when I try to activate the module I get an error:</p>
  
  <pre><code>(basicpython)xxxxx@LinuxBox:~/pythonprojects/basicpython$ python
  Python 2.7.3 (default, Sep 26 2013, 20:08:41) 
  [GCC 4.6.3] on linux2
  Type "help", "copyright", "credits" or "license" for more information.
  &gt;&gt;&gt; import pandas as pd
  Traceback (most recent call last):
   File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  ImportError: No module named pandas
  </code></pre>
  
  <p>When I turn off the virtual environment and do the same thing it works:</p>
  
  <pre><code>(basicpython)xxxxx@LinuxBox:~/pythonprojects/basicpython$ deactivate
  xxxx@LinuxBox:~/pythonprojects/basicpython$ python
  Python 2.7.3 (default, Sep 26 2013, 20:08:41) 
  [GCC 4.6.3] on linux2
  Type "help", "copyright", "credits" or "license" for more information.
  &gt;&gt;&gt; import pandas as pd
  &gt;&gt;&gt; pd
  &lt;module 'pandas' from '/usr/lib/pymodules/python2.7/pandas/__init__.pyc'&gt;
  </code></pre>
  
  <p>Any idea why this might be happening (did I miss an install step with virtualenv?)</p>
  
  <p>EDIT: I installed pandas and other libraries while in the virtual environment, does this not install them in the environment? </p>
  
  <p>EDIT 2: I tried reinstalling the packages while in the virtual environment and the system says they are already there:</p>
  
  <pre><code>(basicpython)xxxx@LinuxBox:~/pythonprojects/basicpython$ sudo apt-get install               
  python-numpy python-scipy python-matplotlib ipython ipython-notebook python-pandas       python-sympy python-nose
    Reading package lists... Done
    Building dependency tree       
    Reading state information... Done
    python-nose is already the newest version.
    python-numpy is already the newest version.
    ipython is already the newest version.
    ipython-notebook is already the newest version.
    python-matplotlib is already the newest version.
    python-pandas is already the newest version.
    python-scipy is already the newest version.
    python-sympy is already the newest version.
    The following packages were automatically installed and are no longer required:
     linux-headers-3.2.0-55-generic-pae gir1.2-ubuntuoneui-3.0 linux-headers-3.2.0-55       libubuntuoneui-3.0-1
     Use 'apt-get autoremove' to remove them.
     0 upgraded, 0 newly installed, 0 to remove and 6 not upgraded.
    (basicpython)xxxxx@LinuxBox:~/pythonprojects/basicpython$ 
  </code></pre>