Added initial layout (with @ChrisBeaumont and @keflavich)
added Adam's work: readers for CASA, FITS
Test fits file generator
Merge pull request #1 from ChrisBeaumont/master

Test files
Merge pull request #2 from keflavich/readerswriters

Add readers for CASA and FITS
added include/exclude properties on mask, implement data_valid
add WCS dropdegenerate tool
degeneracy dropping, minimal data indexing
Fix shapes of test files
Merge pull request #4 from ChrisBeaumont/master

Give stokes axis a single channel for test files
two more manipulation routines
swapaxes used in spectral_cube now
drop degenerate in WCS too
shape returns _data.shape
Merge branch 'minimal_mask_implementation' of git://github.com/keflavich/spectral-cube into minimal_mask_implementation
WCS tests
added docstrings, dropped dropdeg from io
Sanitize orientation of 3+1 cubes
Merge pull request #3 from keflavich/minimal_mask_implementation

added include/exclude properties on mask, implement data_valid
Merge pull request #6 from ChrisBeaumont/orient

Propertly Orient PPV+single stokes data