title: No module named __future__
body: <p>I have error as <code>No module named __future__</code>.
  I use tensorflow and it has Python2.7.
  Once I run a program, I got error as shown below.</p>
  
  <pre><code>import tensorflow
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/home/coie/tensorflow/local/lib/python2.7/site-packages/tensorflow/__init__.py", line 19, in &lt;module&gt;
      from __future__ import absolute_import
  ImportError: No module named __future__
  </code></pre>
  
  <p>How to install <strong>future</strong> into tensorflow's Python?</p>