[setup] Add dev packages requirement

command_line/setup.py

@@ -92,9 +92,11 @@ setup(
     },
 
     install_requires=deps + ["cadbiom", "futures"],
-    # For graphs drawing manually
+    # TODO: use setup.cfg instead of these directives.
+    # => Will allow to finely distinguish dev, and extra packages
     extras_require = {
-        'matplotlib': ["matplotlib<2"],
+        "matplotlib": ["matplotlib<2"], # For graphs drawing manually
+        "dev": ["sphinx<2", "sphinx-argparse"], # For doc
     },
 
     # Tests