Improve user navigation of the project

A simple README, a must for any project.
You should also add "Even the most powerful wizard must consult grimoires as an aid against forgetfulness" as the description of your Github project and provide Github the project website http://grimoire.arrdem.com/.
Merge pull request #29 from BertrandDechoux/patch-1

Improve user navigation of the project
Merge branch 'master' of github.com:arrdem/grimoire into develop
Remove line numbers on examples and source code

Fix #26