forced abspath on reference fp
updated docstrings, added more tests
flake8 compliant
removed the 'uclust' from --uclust_similarity and --uclust_min_consensus_fraction in the parallel assign taxonomy scripts to correspond with the changes in scripts/assign_taxonomy.py
_get_consensus_assignment() moved to TaxonAssigner class
merge resolved
Merge branch 'master' of https://github.com/biocore/qiime into sortmerna-assign-taxonomy

pull from upstream
_tax_assignments_to_consensus_assignments now in TaxonAssigner and used by SortMeRNA and Uclust
Merge pull request #1662 from ekopylova/sortmerna-assign-taxonomy

Add sortmerna to assign_taxonomy.py