Added dtype argument to combiner
Added test for dtype in combiner
Update to astropy_helpers 0.4.3
Merge pull request #179 from mwcraig/update-astropy-helpers

Update to astropy_helpers 0.4.3
Adding the changelog for tracking changes
Added catch if adu is uppercase in fits header
Added dtype argument in docstring
Merge pull request #182 from crawfordsm/fits_adu

Added catch if adu is uppercase in fits header
Merge pull request #181 from crawfordsm/changelog

I'll go ahead and merge, then we can do additions to README and docs separately. Will open issues for those.
Merge pull request #178 from heidtna/line78

Added dtype argument to combiner