add flag for excel. doesnt do anything yet.
change return of edges and vertices to be *unique* (@edges->unique_edges)
testing commit to git
added flag for threshold testing. This is the maximum percentage difference between assemblages for all the types that will be tolerated in adding to a solution. If not specified, then all assemblages will be tested. If you specify -threshold=0.05 only those assemblages that have a maximum type frequency of less than 0.05 will be added to the ends.
Merge branch 'master' of https://github.com/clipo/Seriation

Conflicts:
	perl/IDSS-with-bootstrap.pl