Few things

partial transition to biom 2.0, and su

* support for unique over a column hosts (ie, don't count multiple times for the same host_subject_id)
* use biom_open
* filterSamples -> filter
Agree it's dirty, that's what made the most sense at the time. Maybe it should just be called the `KleeneStar`, though that would be a definite misnomer. I'll rename to `_AllTrue`