starting on full test
temp directory/files working
allow input via either command line or arguments to imagecube.main
calling imagecube.main from test_imagecube
Catching SystemExit exceptions
seems to work without catching
full test of imagecube.main
back to temporary directory for full imagecube test
added download of test data (not yet working)
minor comment changes
imagecube both command-line & interactive. More extensive testing, better logging.