code: function (s) {
              var c = clean( s );
              var all = _.words( c, wordDelimiter );
              var words = _(all).chain()
                      // remove stop words
                      .filter( function (w) {
                          return (stopWords.indexOf( w ) === -1) ;
                      })
                      // apply stemmer
                      .map( function (w) {
                          return stemmer( w );
                      })
                      // collect word frequencies
                      .reduce( function (collect, w) {
                          collect[w] = collect[w] ? collect[w] + 1 : 1 ;
                          return collect;
                      }, {}).value();
              // remove a word from this sentence to reduce redundancy in results
              var remove = function (w) {
                  return delete words[w];
              };
              return {
                  orig: s,
                  words: words,
                  remove: remove
              };
          }
docs: Sentence Module. Creates object with format:
  {orig:String, words:Array<String>, remove:Function}