Merge pull request #52 from angelo234/master

Fixed docs build error

doc/source/conf.py

@@ -33,7 +33,7 @@
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
-extensions = ['sphinx.ext.autodoc', 'sphinxcontrib.napoleon']
+extensions = ['sphinx.ext.autodoc', 'sphinx.ext.napoleon']
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']