vizier: allow list of coordinates (in addition to tables with ra/dec)
vizier: check for isscalar instead of hasattr(len)
need to make an empty poslist before appending to it
add tests for multi-coordinate queries and fix up Vizier tests
Merge pull request #359 from keflavich/vizier_multicoord

vizier: allow list of coordinates (in addition to tables with ra/dec)