code: function uniq(t) {
          var seen = {};
          return t.filter(function(item) {
              return seen.hasOwnProperty(item) ? false : (seen[item] = true);
          })
      }
docs: /*permissions tree example :
  {
  'admin' : ['manage', 'delete']
  'delete': ['write']
  'write' : ['read']
  'read' : [] //Ligne pas obligatoire, implicitement défini dans 'write'
  }