Added new tool to qview which allows measureing and editing sample/line...

Added new tool to qview which allows measureing and editing sample/line registration points between displayed cubes.  Fixes #92

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@4610 41f8697f-d340-4b68-9986-7bafba869bb8