changed the behavior when PFitter reports nbases = 0, to just assume it's because there's no variation at all, which would mean it's single-founder and has an estimated age of zero days.  Really the upper limit of the CI should be higher, but it is not clear what the upper limit would be, and we're not looking at the CI results at this time.
changed the behavior when PFitter reports nbases = 0, to just assume it's because there's no variation at all, which would mean it's single-founder and has an estimated age of zero days.  Really the upper limit of the CI should be higher, but it is not clear what the upper limit would be, and we're not looking at the CI results at this time.

pedlefsen/hiv-founder-id,pedlefsen/hiv-founder-id,pedlefsen/hiv-founder-id