change default values in simmat functions
added top_isomap to viewer
changed simmat_doc to deal with lower dimension similarities
Merge branch 'topic_plot' into doc_similarity
enabled subspace similarity computation in sim_doc_doc and simmat_docs
fixed subspace similarity computation in sim_doc_doc and simmat_docs
Merge branch 'topic_plot' of https://github.com/inpho/vsm into topic_plot
Merge branch 'doc_similarity' into topic_plot
rename isomap/cluster functions