Update README.rdoc

First iteration of the Readme. It's missing screenshot and steps to install which will be added when I'll have extracted the main layout (from pothibo.com) and have a vanilla theme.
Modified Admin title and added a favicon, yay!
Merge branch 'master' of github.com:pothibo/ecrire
Merge branch 'master' into marmite

Conflicts:
	app/views/layouts/application.html.erb