I'm OK with replacing make_otu_network with this code. I'll test this new code out after merge, and once I've done that I can merge a pull request removing make_otu_network. Note that you should not yet remove scripts/make_otu_network.py, but rather replace all functionality with a message to use this new code (see ``scripts/pick_otus_through_otu_table.py`` for an example of how that should work). 

Also, in that pull request, be sure to include a message in ChangeLog.md about this update.