fix CASA .image reading: should not assume 3d by default, since usually
stored as 4d
need to pass CASA's units into SpectralCube
(also, should check for importerror with aplpy quicklooks)
fix a merge mistake in spectral quicklook
Merge pull request #165 from keflavich/casa_cube_loading

Fix CASA cube loading
updated CHANGES
add 'save' to quicklooks
with_mask checks for broadcastable, not equal shape
clean up tests of broadcastability
Merge pull request #166 from keflavich/quicklook_save

Minor fixes: quicklooks, with_mask test
bugfix: with_mask should be usable when no `_mask` is defined
Merge pull request #172 from keflavich/with_mask_no__mask

bugfix: with_mask should be usable when no `_mask` is defined
update apt-get listings (fixes graphviz install issue)
Merge commit 'abb40a2536f522b415cb552b9fdfd796dcb28fe3'

* commit 'abb40a2536f522b415cb552b9fdfd796dcb28fe3':
  update apt-get listings (fixes graphviz install issue)
  bugfix: with_mask should be usable when no `_mask` is defined
  clean up tests of broadcastability
  with_mask checks for broadcastable, not equal shape
  add 'save' to quicklooks
  updated CHANGES
  fix a merge mistake in spectral quicklook
  need to pass CASA's units into SpectralCube (also, should check for importerror with aplpy quicklooks)
  fix CASA .image reading: should not assume 3d by default, since usually stored as 4d