title: PyCharm autocomplete in folder with many projects, both py2 and py3
body: <p>I work on django website with lots of components and modules. </p>
  
  <p>In the same folder and git repository, I also have another closely related projects like data downloaders, transformers, validators, uploaders and utilities. Roots of all projects are many levels deep. Projects use both Python 3 and Python 2, because of some outdated dependencies.</p>
  
  <p>Before today, autocomplete did not work for anything, except maybe major dependencies if I also install them system-wide. Every import was underlined in waved red.</p>
  
  <p>Just now I went to "File/Settings/Project/Project Structure/Add content root", removed default root and added main django website. It works for site, but I can't add root directory since it 'overlaps', so I lost view of tree and this is not acceptable.</p>
  
  <p>How to keep full intact view of source tree and still have autocomplete in all and every sub-project, be it main one or one-off utility ?</p>
  
  <p>PyCharm version is 2016.2.3 (latest), community edition. </p>