Documentation

In order to not get confused between the features of Gondwana and the features of the development version aka 2011-08, we need to keep the main documentation valid for Gondwana and put the documentation relative to the development version in a separate section or page. Most likely a single page won't be enough to write all the changes that are going to happen between Gondwana and its successor.

Note that we do not pretend in this ticket to write the documentation for all the changes between both versions. We only want to start a section that will then gather information about the development version.