Merge pull request #122 from keflavich/wcs_checking_ignore

Add 'ignored keywords' to WCS checking
add documentation, remove locals() reference
out is None check
sum, max, min should not return projections if naxis is not a single
integer
Update to v0.4 of the affiliated package template
Merge pull request #125 from astrofrog/update-template-v0.4

Update to v0.4 of the affiliated package template
Merge pull request #100 from keflavich/apply_publicly

Allow "apply_function" as a public function
First pass at getting spectral-cube's yt interface up to speed with the latest changes in yt 3.0.
Attempting to get some feature parity between yt 2.x and 3.x
Attempting to get better convergence between yt 2.x and 3.0 implementations of to_yt
Adding a yt2world method, cleaning up the documentation a bit
Needed this line
Cleaning up documentation
Followed @astrofrog's suggestion and made these methods take the spectral_cube argument
yt installation line for Travis
Only allow yt tests for recent numpy versions
Only need to test 1.7
Replacing pf with ds to reflect yt 3.0
Some unit tests for yt
Adding assert_array_equal for integer ndarrays