use recommonmark extension in sphinx

doc/conf.py

@@ -30,8 +30,7 @@ release = '1.0.5'
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
-extensions = [
-]
+extensions = ['recommonmark']
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']