Tree command

[bovee]

It would be slick if there was a way to automatically generate a, e.g. Newick, tree from a list of genomes/metagenome files. A simple implementation would only require using the pairwise distance code we already have and then feeding that into a neighbor-joining algorithm that we'd have to write and/or translate over from the One Codex cluster view page.

[schultzm]

or just output whatever metric the user selects as a phylip lower triangle or full matrix (to feed into e.g., quicktree)