A new simplier sub-pixel correlation algorithm has replaced the old 'surface...

A new simplier sub-pixel correlation algorithm has replaced the old 'surface model'.  There are less parameters and less failures now. References #726

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@4522 41f8697f-d340-4b68-9986-7bafba869bb8