Added check for "href is None" in job list with jobrefs, since xlink:href attribute is not required, but optional according to standard uws-schema. Needed for e.g. UWS service of CADC.
Added check for "href is None" in job list with jobrefs, since xlink:href attribute is not required, but optional according to standard uws-schema. Needed for e.g. UWS service of CADC.

aipescience/uws-client