title: Python doesn't find Pyomo
body: <p>I'm stumped on why Python won't import pyomo.  I can find the directory and see it is installed: <br><br></p>
  
  <pre><code>234:pyomo user$ pip show pyomo
  Name: Pyomo
  Version: 5.1.1
  Summary: Pyomo: Python Optimization Modeling Objects
  Home-page: http://pyomo.org
  Author: William E. Hart
  Author-email: wehart@sandia.gov
  License: BSD
  Location: /Users/user/anaconda/lib/python2.7/site-packages
  Requires: appdirs, PyUtilib, six, ply
  </code></pre>
  
  <p>And the directory is at the front of my $PYTHONPATH:</p>
  
  <pre><code>&gt;&gt;&gt; import sys; print sys.path
  ['', '/Users/user/anaconda/lib/python2.7/site-packages/pyomo', '/Users/user/anaconda/lib/python2.7/site-packages', '/Users/user/anaconda/pkgs', '/Users/user/.local/lib/python2.7/site-packages', '/usr/local/lib/python2.7/site-packages',  ... ] 
  </code></pre>
  
  <p>But I still can't import pyomo:</p>
  
  <pre><code>&gt;&gt;&gt; import pyomo.environ
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  ImportError: No module named pyomo.environ
  &gt;&gt;&gt; from pyomo.environ import *
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  ImportError: No module named pyomo.environ
  </code></pre>
  
  <p>What am I missing here?</p>