Changed to no longer call camstats program, now uses instance of Camera...

Changed to no longer call camstats program, now uses instance of Camera Statistics class, consequently fixes temp file bug and resolves #84

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@2630 41f8697f-d340-4b68-9986-7bafba869bb8