Merge pull request #27 in CASA/casaviewer from CAS-13353 to master
* commit '79e0037a8b1148fbb28fbf339eab4517f30d9057':
CAS-13335: imview must work on non linux systems that don't support gui=False, set to False but still generate output
CAS-13353: added test_imview.py to casaviewer repository for use with CASA 6