Fixed a round-off bug in the Reduce class, which caused problems in the reduce...

Fixed a round-off bug in the Reduce class, which caused problems in the reduce application and the qview, File/Save As function.  Fixes #1385.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@4967 41f8697f-d340-4b68-9986-7bafba869bb8