Don't drop single columns/rows down to a vector
Don't drop single columns/rows down to a vector

bcbio metadata containing only description and NA batch, phenotype columns previously would drop to a character vector. Never ran into this with unit testing because we always provided additional sample metadata columns, which prevented this from happening.

Co-Authored-By: marypiper <6c5987ba0b384f8aec32e5ca6d79fa5942448330@users.noreply.github.com>

steinbaugh/basejump,seqcloud/seqcloudR,steinbaugh/seqcloudr