title: Error "Attempted relative import" on Sphinx-doc
body: <p>I tried to use the autodocumentation of Sphinx-doc. I want to fix the following problem. At the moment, no solutions from StackOverflow worked.
  Is it due to the structure of my project or the way I chose to import my modules ?</p>
  
  <p>Given structure of files :</p>
  
  <pre><code>project
   |_ src
   |   |_ pre_processing
   |   |     |_ fileInfo.py
   |   |
   |   |_ utils
   |         |_ folder.py
   |_ test
   |      
   |_ doc
   |   |_ doc_user
   |        |_ build
   |        |_ source
   |             |_config.py
  </code></pre>
  
  <p>Following config sys.path :</p>
  
  <pre><code>import os
  import sys
  sys.path.insert(0, os.path.abspath('../../../src/'))
  </code></pre>
  
  <p>I've got some relative imports in fileInfo.py as :</p>
  
  <pre><code>from ..utils.folder import get_files_directory
  </code></pre>
  
  <p>Terminal error</p>
  
  <pre><code>WARNING: autodoc: failed to import module 'pre_processing.fileInfo'; the following exception was raised:
  Traceback (most recent call last):
  
  File "/home/florian-stage/miniconda/envs/gd/lib/python3.5/site-packages/sphinx/ext/autodoc/importer.py", line 140, in import_module
  __import__(modname)
  
  File "/home/florian-stage/Projet-2018/pg_georef_data-master/arbo propre/src/pre_processing/fileInfo.py", line 12, in &lt;module&gt;
  from ..utils.folder import get_files_directory
  ValueError: attempted relative import beyond top-level package
  </code></pre>