fix two bugs: 1. Exception -> ValueError/KeyError 2. 'if coordinate' ->
if coordinate is not None
fix treatment of masks in ALFALFA and Exception testing in simbad,
vizier
tiny change; this was NOT failing locally!
unfortunate hack.  str(ex) doesn't work, must use str(ex.args[0])
Merge pull request #276 from keflavich/bugfixes_276

Many new and exciting failures in master