WORDCLOUD: X.X : smart word selection

Uses the CQL defined here https://groupes.renater.fr/wiki/txm-users/public/faq#comment_faire_un_index_sans_les_mots-outils_ou_grammaticaux
To select the words to use for the WordCloud

(from redmine: issue id 496, created on 2014/01/06 by Matthieu Decorde)

added type::feature + 1 deleted label

changed milestone to %WordCloud X.X