quicklook: backup plan if celestial + spectral axes ("PV" diagram)
fix a yt version check in the tests: yt-dev versions were not parsed
properly
Merge pull request #151 from keflavich/yt_version_check

Minor: fix a yt version check in the tests
Combined commits: fix a minor issue with np.nansum behavior changing
from 1.8-1.9
add numpy 1.8 nanfunctions to ensure np1.8 = np1.9 behavior

udpate tests

moments no longer uses np.nansum (np_compat.nansum instead)

remove all but nansum, nanmin, nanmax

import things that needed to be imported (oops)

correct imports and add support functions for numpy 1.7.  If this fails
on 1.6, 3.2, I suggest we drop support for them

completely copying over numpy functions was way too much and would have
lead to a huge maintenance burden.  Instead, just overload nansum and
leave the rest untouched

remove np_compat; we're just going to change the tests

remove np_compat

1.9 nanish override; everything else gets to stay the same
separate concerns as per @ChrisBeaumont's suggestion
Merge pull request #150 from keflavich/np18nan

numpy 1.8 compatibility for NAN functions
don't convert to np.float - can double data size!  (very bad for large
cubes)
apparently data MUST be coerced to floating point unless it's already a
float.  I don't understand why.  Tests are still broken in a place I
don't understand
cleanup data[view]/dtype logic
add np 1.9 to travis as the default, with the expectation that this will
break everything
travis: more tests with 1.8 vs 1.9.  This will still fail, but at least
it shouldn't error
allbadtonan wrapper instead of a single-case override; allows general
use and application within the test suite too
add the @!#$ file
Merge pull request #149 from keflavich/nofloat

don't convert to np.float - can double data size!
Merge pull request #140 from keflavich/quicklook_unmatchedaxes

Quicklook: Do something (not something smart) if there are unmatched celestial axes
preserve the spectral units when creating an output header
add tests
Merge pull request #154 from keflavich/preserve_spectral_unit

Preserve the spectral units when creating an output header
preserving units: most of this work was already done and just wasn't
passed to header.  Added unit preservation (based on header) to __init__
now
fix bug + regression test