Uses hclust() with the ``ward.D'' method on 1-S with S from make.similarity.matrix
Warning: for 'negative weight' phrases this method does not do well since it ignores negative documents.
cluster.phrases(result, num.groups = 5, plot = TRUE, yaxt = "n", ylab = "", sub = "", main = "Association of Phrases", ...)make.appearance.matrix;
make.phrase.correlation.chart;
make.similarity.matrix