title: How to setup PyCharm for multiple projects
body: <p>I want to set up PyCharm to work on a set of Python projects in a single window.</p>
  <p>Lets say I have this projects structure.</p>
  <pre><code>~/src
  ├── py_project1
  ├── py_project2
  ├── py_project3
  ├── other_lang_proj1
  └── other_lang_proj2
  </code></pre>
  <p>A system PYTHONPATH of <code>/Library/Python/2.7/site-packages:/usr/local/lib/python2.7/site-packages:/opt/proprietary/packages</code></p>
  <p>and some packages at</p>
  <pre><code>/opt/proprietary/packages
  ├── project1
  ├── project2
  └── project3
  </code></pre>
  <p>How do I add the <code>~/src/py_project*</code> projects to a single PyCharm window and have them see all of the packages in PYTHONPATH and <code>/opt/proprietary/packages/project*</code>?</p>
  <p>Moving directories is not optional, and I don't want virtualenv. I want to configure PyCharm once for all of the open projects. For the record the PYTHONPATH works just fine for this setup everywhere but PyCharm.</p>