Fixed issue with alphacube propagation during ifft. noproj no longer...

Fixed issue with alphacube propagation during ifft. noproj no longer propagates the alphacube group. Fixes #4907.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@8000 41f8697f-d340-4b68-9986-7bafba869bb8