[repo] Move README file to a README.md file rendered by Gitlab, with extra links to doc

README → README.md

+Weboob
+======
+
+
 Weboob is a project which provides a core library, modules and applications.
 
-Overview
---------
+## Overview
 
 The core library defines capabilities: features common to various websites.
-For example, http://www.youtube.com/ and http://www.dailymotion.com/ both
-provide videos; Weboob defines the "CapVideo" capability for them.
+For example, [Youtube](http://www.youtube.com/) and
+[Dailymotion](http://www.dailymotion.com/) both provide videos; Weboob defines
+the `CapVideo` capability for them.
 
 Each module interfaces with a website and implements one or many of these
 capabilities. Modules can be configured (becoming a "backend"), which means
@@ -21,9 +25,22 @@ or in pipes.
 The core library provides base classes which help developers write
 modules and applications.
 
+
+## Installation
+
+Installation is described on [the website](http://weboob.org) or in the
+[INSTALL](INSTALL) file.
+
+## License
+
 Weboob is written in Python and is distributed under the AGPLv3+ license.
 
+## Documentation
+
+For more information, please go to [the official website](http://weboob.org/).
 
-For more information, please go to the official website at http://weboob.org/
+Some extra info is available in the [Gitlab
+wiki](https://git.weboob.org/weboob/devel/wikis/home).
 
-Installation is described on the website or in the INSTALL file.
+If you are a developper and looking for how to write a module or contribute to
+Weboob, you can have a look at the [developper documentation](http://dev.weboob.org/).