try moving CASA to 'extras' to get it to install _after_ the basic dependncies (i.e., numpy) are installed.  I'm not sure this is right, still learning what tox does
try moving CASA to 'extras' to get it to install _after_ the basic
dependncies (i.e., numpy) are installed.  I'm not sure this is right,
still learning what tox does

radio-astro-tools/spectral-cube,keflavich/spectral-cube,e-koch/spectral-cube