improvements on the dev documentation website

- new home page (inspired from the python's one)
- add a "How to contribute" page
- add logo/favicon
- more customizations

docs/source/index.rst

@@ -1,9 +1,17 @@
 Weboob
 ======
 
-This is the developer documentation. If you are not a developer and you are looking for information about the project, check the `official website <http://weboob.org>`.
+Weboob (Web Outside Of Browsers) provides:
 
-Contents:
+* :doc:`applications <api/tools/application/index>` to interact with websites
+* :doc:`modules </guides/module>`, each one handles a specific website
+* a :doc:`core library <api/core/index>` providing all the features needed by backends
+* :doc:`tools <api/tools/index>` to help develop backends and applications
+
+Weboob is written in Python and is distributed under the AGPLv3+ license.
+
+.. note::
+ This is the developer documentation. If you are not a developer and you are looking for information about the project, check the `official website <http://weboob.org>`_.
 
 .. toctree::
    :maxdepth: 2
@@ -12,9 +20,6 @@ Contents:
    guides/index
    api/index
 
-Indices and tables
-==================
-
 * :ref:`genindex`
 * :ref:`modindex`
 * :ref:`search`