Include evolution of the generation script in the rebuild test

This changeset modifies the hash code saved in db for the skip test
to include the tracking of the script itself. That means that all
the pages of the book are regenerated whenever the script changes.
Process tables in the book

Preprocess the markdown files to change the tables into a format which
RedCarpet can convert to a HTML table. Then add a class to this table so
that we can apply css on it.