Minor tidying up
moved writer to io/fits.py
remove obsolete method
Fix stokes WCS modification
Fixed failures
Fixed spectral_slab
Fix tests for Python 3
Renamed wcs_manipulation to wcs_utils
PEP8
Added directory for docs
spec out subcube
Make SpectralCube stokes-agnostic
Moved orient utilities to cube_utils
Make FITS loader deal with 3- and 4-d data
Fix 4-d cube reading
Fix WCS re-ordering
Fix FITS writing
Added TODO
Address comments by @keflavich
Merge pull request #17 from astrofrog/stokes-refactor

Stokes refactor