Fixed a bug in findimageoverlaps that prevented fully enveloped images from...

Fixed a bug in findimageoverlaps that prevented fully enveloped images from being recorded as overlaps.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@6960 41f8697f-d340-4b68-9986-7bafba869bb8